Openbsd
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Remote, unauthenticated attackers who can reach an explicitly enabled OpenBSD ldapd instance can complete an LDAP Bind as another identity because delegated BSD authentication results are correlated only by the LDAP child process's client file descriptor and LDAP message ID. When a connection closes and a later connection reuses the same file descriptor and message ID, the earlier successful authentication result is delivered to the new connection, granting the attacker the other user's identity (CWE-863, incorrect authorization); the same code path also dereferences a missing connection and crashes the daemon for denial of service. Exploitation is gated by two prerequisites: ldapd must be manually enabled (it is not on by default) and configured to use delegated BSD authentication, and the identity takeover additionally requires winning a timing/resource-reuse race to land on the exact fd+message-ID pair, which is why both the CVSS 4.0 vector (AC:H/AT:P) and the independent CVSS 3.1 assessment (AC:H) rate the attack complexity as high despite PR:N. The defect is confirmed by an upstream OpenBSD source fix and errata 7.8/057 and 7.9/021; no public exploit code and no CISA KEV active-exploitation entry were identified at time of analysis.
Memory corruption in the OpenSSH client (ssh) before 10.4 lets a malicious or compromised SSH server trigger a use-after-free on the connecting client by changing its host key during a key re-exchange (rekey), potentially leading to information disclosure or code execution in the client process. Only the client side is affected; the server is not vulnerable. There is no public exploit identified at time of analysis and it is not on CISA KEV, and EPSS is low (0.25%, 16th percentile), but the flaw is fixed in OpenSSH 10.4/10.4p1.
Denial of service in OpenSSH sshd before 10.4 lets remote unauthenticated attackers exhaust server resources by driving excessive authentication attempts, because the MaxAuthTries cap was not correctly enforced for the GSSAPIAuthentication path. Only deployments that have enabled GSSAPI-based authentication are exposed, and there is no public exploit identified at time of analysis. EPSS is low (0.34%, 26th percentile) and CISA SSVC records no observed exploitation, so this is a real but non-urgent availability issue rather than a code-execution threat.
Security-control bypass in OpenSSH sshd before 10.4 causes the DisableForwarding=yes hardening directive to be silently ignored when PermitTunnel=yes is also set, so tun-device forwarding remains available despite an administrator's explicit policy to disable all forwarding. Affected operators are those who rely on DisableForwarding as a defense-in-depth restriction; the flaw lets an authenticated user establish layer-2/3 tunnels the configuration was meant to forbid. There is no public exploit identified at time of analysis, EPSS is low (0.13%, 3rd percentile), and it is not on CISA KEV.
Local privilege escalation to root in OpenBSD through 7.9 arises from a use-after-free in the System V semaphore subsystem (sys/kern/sysv_sem.c). An authenticated local user calling sys_semget() can trigger a context-switch use-after-free after tsleep(), where a freed semid_ds_kern structure is reused, enabling kernel memory corruption and full root compromise. There is no public exploit identified at time of analysis, EPSS probability is low (0.12%), and the issue is not listed in CISA KEV; the upstream fix adds reference counting (sem_ref/sem_rele) around the sleep window.
Authentication bypass in OpenBSD's sppp PAP handler (sppp_pap_input in sys/net/if_spppsubr.c) lets an adjacent attacker on a PPP link authenticate without valid credentials by supplying zero-length name/password fields, which the kernel only bounds-checked against an upper limit (AUTHMAXLEN) instead of the exact expected credential length. All OpenBSD builds before commit 076e2b1 that terminate PPP sessions with PAP authentication are affected. Publicly available exploit code exists (an Argus Systems PoC script) and a vendor fix is available, though EPSS is low (0.21%, 12th percentile) and the flaw is not in CISA KEV, so this is proof-of-concept rather than confirmed active exploitation.
Argument/command injection in OpenSSH before 10.3 lets shell metacharacters embedded in an untrusted username trigger command execution on the SSH-client host. It affects deployments that both feed an attacker-influenced username to the ssh command line and use a non-default ssh_config where %-token expansion (e.g. in ProxyCommand/LocalCommand) is enabled. There is no public exploit identified at time of analysis, EPSS is negligible (0.01%), and it is not in CISA KEV; a fixed release (10.3/10.3p1) is available.
OpenSSH before version 10.3 mishandles the authorized_keys principals option when a principals list is combined with a Certificate Authority that uses certain comma character patterns, allowing authenticated local or remote users to disclose sensitive authorization information or manipulate authentication decisions. This vulnerability affects all OpenSSH versions prior to 10.3p1 and requires authenticated access (PR:L) with non-trivial attack complexity (AC:H), resulting in partial confidentiality and integrity impact. No public exploit code or active exploitation has been identified at time of analysis.
Privilege-escalation exposure in OpenSSH before 10.3 (fixed in 10.3p1) where scp, when run by root using the legacy SCP protocol flag -O and without -p (preserve mode), may write a downloaded file with setuid or setgid bits set, contrary to user expectation. A malicious or compromised SSH server (or a man-in-the-middle on the transfer) could thereby cause an attacker-controlled binary to land on disk as a setuid/setgid-root executable, enabling local privilege escalation when it is later run. There is no public exploit identified at time of analysis, EPSS is very low (0.04%), and CISA SSVC rates exploitation as 'none' though technical impact as 'total'.
smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session, as demonstrated. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
OpenBSD through 6.6 allows local users to escalate to root because a check for LD_LIBRARY_PATH in setuid programs can be defeated by setting a very small RLIMIT_DATA resource limit. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available.
OpenSSH servers prior to 10.6 fail to enforce the 'restrict' keyword in authorized_keys against tunnel (tun/tap) forwarding, letting a user who already holds a restricted key open a forwarding tunnel that the administrator explicitly intended to block. This is a control-bypass rather than an access-control failure: the attacker must already possess a valid SSH key provisioned with 'restrict' (assessed CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N), and the flaw only matters on servers older than 10.6 where tunnel forwarding was the specific capability the keyword was relied on to deny. Impact is limited to integrity (establishing the forwarding channel) with no confidentiality or availability loss, the base score is 2.5, and no public exploit code or CISA KEV activity is identified at time of analysis.
Availability degradation in OpenSSH before 10.6 occurs because sshd and ssh fail to enforce the maximum packet length while decompressing highly compressed SSH data, allowing a peer on a connection with negotiated SSH compression to trigger excessive resource consumption. Exploitation requires compression (zlib or zlib@openssh.com) to be negotiated-often not the case on modern OpenSSH servers where compression is disabled or delayed until after authentication-and an active malicious or compromised SSH peer; the independent assessment scores this as remote, network-reachable, unauthenticated with low availability impact and no confidentiality or integrity impact. No public exploit identified at time of analysis.
ssh-keygen in OpenSSH versions before 10.6 can assign incorrect expiration timestamps to generated certificates when a Daylight Saving Time transition is mishandled, producing a bounded integrity error in the certificate's validity window. The issue is local: it requires a user to run ssh-keygen for certificate creation or signing, and it only manifests around DST changes, with slightly more pronounced effects noted for certain Antarctic time zones. With a CVSS score of 2.5 and no public exploit identified at time of analysis, this is a low-priority correctness bug rather than a remotely exploitable security flaw.
The sshd and ssh components of OpenSSH before 10.6 can be made to negotiate and use the LZ77 dictionary-coder compression scheme, a behavior the 'Crossing the Streams' research (arXiv 2609.07709) identifies as contraindicated because compression-derived information leakage can be measured from an observed session. A remote, unauthenticated attacker who can observe and influence the target connection and repeatedly sample it may recover a limited amount of confidential data, but only where the vulnerable compression mode is actually in use; integrity and availability are unaffected. This is a low-severity, low-priority issue (CVSS 3.1 base 3.7; AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N) despite being network-reachable and unauthenticated, because exploitation demands an active compression configuration, a privileged observation vantage point, and sustained measurement - no public exploit code has been identified at time of analysis and there is no confirmed active exploitation (CISA KEV).
Information disclosure in OpenSSH sshd before 10.6 can occur when GSSAPIAuthentication is enabled and multiple authentication attempts are made, allowing authentication state from a prior attempt to persist. This is a low-priority issue despite affecting a ubiquitous product, because default OpenSSH configurations set GSSAPIAuthentication to no and exploitation also requires a functioning Kerberos/GSSAPI environment. The issue carries a low severity rating, and no public exploit identified at time of analysis.
Credentials may persist in sshd after a failed GSSAPIAuthentication attempt in OpenSSH before 10.6, potentially leading to low-impact information disclosure. This issue requires GSSAPIAuthentication to be enabled (not the default), a local low-privilege attacker with an existing foothold, and user interaction; it cannot be exploited remotely or without authentication. No public exploit code has been identified, and the overall risk is low-priority.
Directory traversal in the OpenSSH sftp client before 10.6 can cause files to be written to unintended locations when a user performs a recursive copy operation against an attacker-controlled or compromised SFTP server. Exploitation requires the victim to initiate a recursive transfer such as get -r or put -r, and the malicious server supplies crafted path/filename entries containing traversal components; this is a client-side trust issue, not a flaw in an exposed sshd service. No public exploit identified at time of analysis, and the assessed CVSS 3.1 score is 4.2 with high attack complexity and user interaction required.
OpenBSD's 802.11 TKIP implementation deauthenticates all wireless clients and blocks reassociation for up to 90 seconds when an attacker within RF range sends two malformed TKIP frames separated by more than 60 seconds. The root cause is an inverted comparison operator in ieee80211_michael_mic_failure() that reverses the 60-second MIC failure countermeasure window: out-of-window failures incorrectly trigger the IEEE 802.11i countermeasure (a DoS), while in-window failures that should trigger the countermeasure are silently discarded, leaving active TKIP key-recovery attacks completely undetected. A publicly available exploit exists per the Argus Systems advisory; no KEV listing at time of analysis.
OpenSSH sshd before version 10.5 fails to enforce the `restrict` keyword in `authorized_keys` against tunnel forwarding, allowing a constrained SSH key holder to establish tun-device tunnels that the administrator explicitly intended to block. The flaw affects all OpenSSH releases prior to 10.5 and is classified as a policy-enforcement bypass with low integrity impact. No active exploitation is confirmed per SSVC (exploitation: none) and the vulnerability is absent from the CISA KEV catalog, placing this firmly in the low-urgency tier despite OpenSSH's near-ubiquitous deployment footprint.
Use-after-free (CWE-416) in OpenSSH's ssh client component affects all releases before version 10.5, triggered when a specific pair of remote-forwarding operations occur concurrently, causing access to freed realloc'd memory. A malicious or compromised SSH server could exploit this race condition against a connecting client to achieve partial information disclosure or limited memory corruption. No public exploit has been identified and CISA SSVC rates exploitation as none with partial technical impact, consistent with the moderate CVSS score of 4.8.
OpenSSH ssh-agent before version 10.5 permits remote execution of agent operations - including adding authentication tokens and using SSH keys - that were architecturally intended to be restricted to local access only. The trust boundary failure stems from a misinteraction between the agent locking mechanism and the session-bind@openssh.com extension, allowing an authenticated remote actor to cross the local/remote privilege boundary. No public exploit has been identified at time of analysis, and SSVC assessment confirms no current exploitation activity; however, the network-accessible vector and ubiquitous deployment footprint of OpenSSH make patching to 10.5 the appropriate response for any environment using agent forwarding.
OpenSSH sshd before version 10.4 fails to consistently enforce its built-in minimum authentication delay, undermining the rate-limiting defense designed to slow credential-guessing attacks against SSH services. All OpenSSH releases prior to 10.4 are affected across all platforms, enabling unauthenticated remote attackers to submit authentication attempts at a rate higher than the daemon intends to permit. No public exploit code has been identified and the vulnerability is absent from CISA KEV; however, the trivial attack complexity combined with OpenSSH's near-universal deployment footprint makes prompt patching appropriate.
OpenSSH sshd before version 10.4 silently ignores the GSSAPIStrictAcceptorCheck configuration directive when the server is integrated with Windows Active Directory, defeating a security control that administrators rely on to enforce GSSAPI acceptor name validation during Kerberos-based SSH authentication. This undocumented behavior means AD-joined SSH servers may accept GSSAPI authentications against unintended Kerberos service principals regardless of how the option is configured, yielding limited confidentiality and integrity impact. No public exploits or active exploitation have been identified; the CVSS AC:H rating reflects the specific environmental prerequisites required for exploitation.
OpenSSH's internal-sftp subsystem silently discards all command-line arguments beyond position 9, allowing authenticated SFTP users to bypass security restrictions that administrators intended to enforce via those later-positioned arguments. All OpenSSH releases before 10.4 are affected when sshd_config supplies more than nine arguments to the internal-sftp subsystem, which is a non-default but legitimate administrative pattern used for directory restriction, read-only enforcement, and umask control. No public exploit has been identified and this vulnerability is not listed in the CISA KEV catalog; however, sites relying on complex internal-sftp argument chains for access policy enforcement face a direct, silent policy bypass.
Path traversal in the scp utility of OpenSSH before 10.4 causes files to be written into the parent directory of the intended destination during remote-to-remote copy operations. The root cause is CWE-23 (Relative Path Traversal): scp fails to canonicalize or sanitize paths when relaying data between two remote hosts, allowing an attacker controlling a malicious endpoint to influence where transferred files land. No public exploit identified at time of analysis, and active exploitation has not been confirmed by CISA KEV; the CVSS AC:H and UI:R metrics significantly constrain real-world exploitability.
Path traversal in the OpenSSH sftp client before version 10.4p1 allows an attacker-controlled server to write downloaded files outside the user's intended target directory when the 'sftp server:/path .' bulk-download syntax is used. Affected are all OpenSSH deployments where users sftp from untrusted or attacker-controlled hosts, which in practice spans virtually every Linux and Unix environment. No public exploit has been identified at time of analysis and the vulnerability is not listed in CISA KEV, though the ubiquity of OpenSSH elevates aggregate exposure despite the moderate per-instance severity.
Kernel stack memory disclosure in OpenBSD's MPLS input processing exposes arbitrary kernel stack contents to unauthenticated remote attackers via crafted MPLS frames. The flaw exists in `mpls_do_error` within `sys/netmpls/mpls_input.c` (revision 1.81), where a label-stack iterator lacked an upper-bounds guard, allowing a 16-label frame with no Bottom-of-Stack bit to drive an out-of-bounds read. A publicly available exploit exists per the Argus Systems advisory; this vulnerability is not confirmed as actively exploited in the CISA KEV catalog, and the CVSS 4.0 score is 6.9.
Denial-of-service in OpenBSD slaacd and rad daemons allows local network attackers to trigger infinite loops by sending crafted ICMPv6 Neighbor Discovery packets with zero-length options, causing affected daemons to hang due to missing validation of the nd_opt_len field before arithmetic operations. OpenBSD versions through 7.8 are affected. No evidence of active exploitation has been identified.
OpenSSH before 10.3 fails to confirm connection multiplexing in proxy-mode sessions, allowing local attackers with user interaction to bypass intended access controls and potentially manipulate multiplexed connections. The vulnerability affects OpenSSH versions prior to 10.3p1 and requires local access with user interaction (UI:R) on the affected system; while the CVSS score is low (2.5) and integrity impact is limited, the omission of confirmation mechanisms in proxy-mode multiplexing creates a logic flaw that could enable unauthorized session hijacking or redirection in multi-user environments.
OpenSSH before 10.3 incorrectly interprets ECDSA algorithm specifications in PubkeyAcceptedAlgorithms and HostbasedAcceptedAlgorithms configuration options, allowing authenticated users to authenticate using unintended ECDSA variants. The vulnerability requires authenticated network access and high attack complexity, resulting in a low CVSS score of 3.1 with integrity impact but no confidentiality or availability loss. No public exploit code or active exploitation has been documented.
Vulnerability in the OpenSSH GSSAPI delta included in various Linux distributions. This vulnerability affects the GSSAPI patches added by various Linux distributions and does not affect the OpenSSH upstream project itself.
Server-side denial of service in openrsync through 0.5.0, including the copy shipped in OpenBSD through 7.8 and portable builds on other platforms, allows a client that has been accepted by the rsync server to crash the server process with a SIGSEGV. The attacker triggers the fault by specifying a block length of zero during the block-data exchange phase, a state the receiver never validates against the remaining byte count; impact is limited to availability (C:N/I:N/A:H, medium severity at CVSS 3.1 base 5.3) with no code execution or data exposure. No confirmed active exploitation (not in CISA KEV) and no public exploit identified at time of analysis, and EPSS is low at 0.28% (19th percentile), so practical risk is concentrated in servers that accept rsync sessions from untrusted clients.
In sshd in OpenSSH before 10.0, the DisableForwarding directive does not adhere to the documentation stating that it disables X11 and agent forwarding. Rated medium severity (CVSS 4.3), this vulnerability is no authentication required, low attack complexity.
In OpenBSD 7.6 before errata 006 and OpenBSD 7.5 before errata 015, traffic sent over wg(4) could result in kernel crash. Rated high severity (CVSS 7.1), this vulnerability is remotely exploitable, low attack complexity.
A flaw was found in the OpenSSH package. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. Epss exploitation probability 42.5% and no vendor patch available.
A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, no authentication required. Epss exploitation probability 60.0%.
In OpenBSD 7.4 before errata 014, vmm(4) did not restore GDTR limits properly on Intel (VMX) CPUs. Rated medium severity (CVSS 6.2), this vulnerability is low attack complexity.
In OpenBSD 7.4 before errata 006 and OpenBSD 7.3 before errata 020, httpd(8) is vulnerable to a NULL dereference when handling a malformed fastcgi request. Rated high severity (CVSS 8.7), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This NULL Pointer Dereference vulnerability could allow attackers to crash the application by dereferencing a null pointer.
In OpenBSD 7.5 before errata 009 and OpenBSD 7.4 before errata 022, exclude any '/' in readdir name validation to avoid unexpected directory traversal on untrusted file systems. Rated medium severity (CVSS 4.1), this vulnerability is low attack complexity. This Path Traversal vulnerability could allow attackers to access files and directories outside the intended path.
In OpenBSD 7.5 before errata 008 and OpenBSD 7.4 before errata 021, avoid possible mbuf double free in NFS client and server implementation, do not use uninitialized variable in error handling of NFS. Rated critical severity (CVSS 9.2), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Remote code execution in OpenSSH's sshd server (regression of CVE-2006-5051) allows unauthenticated remote attackers to exploit a signal handler race condition by failing to authenticate within the LoginGraceTime window, potentially yielding root-level code execution on glibc-based Linux systems. The flaw - widely known as 'regreSSHion' - affects numerous distributions and vendor appliances including Ubuntu 23.10/24.04, AlmaLinux 9, SonicWall SMA firmware, Arista EOS, NetApp ONTAP, and others. Publicly available exploit code exists and EPSS scores it at 48.06% (98th percentile), reflecting very high exploitation likelihood, though it is not currently listed in CISA KEV.
NFS in a BSD derived codebase, as used in OpenBSD through 7.4 and FreeBSD through 14.0-RELEASE, allows remote attackers to execute arbitrary code via a bug that is unrelated to memory corruption. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
OpenSSH through 10.0, when common types of DRAM are used, might allow row hammer attacks (for authentication bypass) because the integer value of authenticated in mm_answer_authpassword does not. Rated high severity (CVSS 7.0). No vendor patch available.
In ssh in OpenSSH before 9.6, OS command injection might occur if a user name or host name has shell metacharacters, and this name is referenced by an expansion token in certain situations. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 16.5%.
In ssh-agent in OpenSSH before 9.6, certain destination constraints can be incompletely applied. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. Public exploit code available and EPSS exploitation probability 53.6%.
OpenBSD 7.3 before errata 014 is missing an argument-count bounds check in console terminal emulation. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. This Missing Authorization vulnerability could allow attackers to access resources or perform actions without proper authorization checks.
The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if an agent is forwarded to an attacker-controlled system. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
A double free or use after free could occur after SSL_clear in OpenBSD 7.2 before errata 026 and 7.3 before errata 004, and in LibreSSL before 3.6.3 and 3.7.x before 3.7.3. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
ascii_load_sockaddr in smtpd in OpenBSD before 7.1 errata 024 and 7.2 before errata 020, and OpenSMTPD Portable before 7.0.0-portable commit f748277, can abort upon a connection from a local, scoped. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
ssh-add in OpenSSH before 9.3 adds smartcard keys to ssh-agent without the intended per-hop destination constraints. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In OpenBSD 7.2, a TCP packet with destination port 0 that matches a pf divert-to rule can crash the kernel. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Uncontrolled Resource Consumption vulnerability could allow attackers to cause denial of service by exhausting system resources.
OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required. Public exploit code available and EPSS exploitation probability 88.3%.
slaacd in OpenBSD 6.9 and 7.0 before 2022-03-22 has an integer signedness error and resultant heap-based buffer overflow triggerable by a crafted IPv6 router advertisement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
engine.c in slaacd in OpenBSD 6.9 and 7.0 before 2022-02-21 has a buffer overflow triggerable by an IPv6 router advertisement with more than seven nameservers. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
An issue was discovered in OpenSSH before 8.9. Rated low severity (CVSS 3.7), this vulnerability is remotely exploitable, no authentication required. This Improper Authentication vulnerability could allow attackers to bypass authentication mechanisms to gain unauthorized access.
sshd in OpenSSH 6.2 through 8.x before 8.8, when certain non-default configurations are used, allows privilege escalation because supplemental groups are not initialized as expected. Rated high severity (CVSS 7.0).
x509_constraints_parse_mailbox in lib/libcrypto/x509/x509_constraints.c in LibreSSL through 3.4.0 has a stack-based buffer over-read. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 14.6%.
ssh-agent in OpenSSH before 8.5 has a double free that may be relevant in a few less-common scenarios, such as unconstrained agent-socket access on a legacy operating system, or the forwarding of an. Rated high severity (CVSS 7.1), this vulnerability is remotely exploitable.
iked in OpenIKED, as used in OpenBSD through 6.7, allows authentication bypass because ca.c has the wrong logic for checking whether a public key matches. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
scp in OpenSSH through 8.3p1 allows command injection in the scp.c toremote function, as demonstrated by backtick characters in the destination argument. Rated high severity (CVSS 7.4), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
The client side in OpenSSH 5.7 through 8.4 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required.
The scp client in OpenSSH 8.2 incorrectly sends duplicate responses to the server upon a utimes system call failure, which allows a malicious unprivileged user on the remote server to overwrite. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
A vulnerability was discovered in Linux, FreeBSD, OpenBSD, MacOS, iOS, and Android that allows a malicious access point, or an adjacent user, to determine if a connected user is using a VPN, make. Rated high severity (CVSS 7.4), this vulnerability is low attack complexity. No vendor patch available.
OpenBSD 6.6, in a non-default configuration where S/Key or YubiKey authentication is enabled, allows local users to become root by leveraging membership in the auth group. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
libc in OpenBSD 6.6 allows authentication bypass via the -schallenge username, as demonstrated by smtpd, ldapd, or radiusd. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
xlock in OpenBSD 6.6 allows local users to gain the privileges of the auth group by providing a LIBGL_DRIVERS_PATH environment variable, because xenocara/lib/mesa/src/loader/loader.c mishandles. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
In OpenBSD 6.6, local users can use the su -L option to achieve any login class (often excluding root) because there is a logic error in the main function in su/su.c. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
OpenSSH 7.7 through 7.9 and 8.x before 8.1, when compiled with an experimental key type, has a pre-authentication integer overflow if a client or server is configured to use a crafted XMSS key. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available.
OpenBSD kernel version <= 6.5 can be forced to create long chains of TCP SACK holes that causes very expensive calls to tcp_sack_option() for every incoming SACK packet which can lead to a denial of. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
An issue was discovered in OpenSSH 7.9. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. Public exploit code available.
In OpenSSH 7.9, due to accepting and displaying arbitrary stderr output from the server, a malicious server (or Man-in-The-Middle attacker) can manipulate the client output, for example to use ANSI. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, no authentication required. Public exploit code available.
An issue was discovered in OpenSSH 7.9. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, no authentication required.
Remotely observable behaviour in auth-gss2.c in OpenSSH through 7.8 could be used by remote attackers to detect existence of users on a target system when GSS2 is in use. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Exposure of Sensitive Information vulnerability could allow attackers to access sensitive data that should not be disclosed.
OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed,. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
tss_alloc in sys/arch/i386/i386/gdt.c in OpenBSD 6.2 and 6.3 has a Local Denial of Service (system crash) due to incorrect I/O port access control on the i386 architecture. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
LibreSSL before 2.6.5 and 2.7.x before 2.7.4 allows a memory-cache side-channel attack on DSA and ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP. Rated medium severity (CVSS 4.7). No vendor patch available.
The int_x509_param_set_hosts function in lib/libcrypto/x509/x509_vpm.c in LibreSSL 2.7.0 before 2.7.1 does not support a certain special case of a zero name length, which causes silent omission of. Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, no authentication required.
sshd in OpenSSH before 7.4 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz,. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
The process_open function in sftp-server.c in OpenSSH before 7.6 does not properly prevent write operations in readonly mode, which allows attackers to create zero-length files. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use-after-free vulnerability in OpenSMTPD before 5.7.2 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via vectors involving req_ca_vrfy_smtp and. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 10.1%.
The OpenBSD qsort() function is recursive, and not randomized, an attacker can construct a pathological input array of N elements that causes qsort() to deterministically recurse N/4 times. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 17.0%.
A flaw exists in OpenBSD's implementation of the stack guard page that allows attackers to bypass it resulting in arbitrary code execution using setuid binaries such as /usr/bin/at. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
LibreSSL 2.5.1 to 2.5.3 lacks TLS certificate verification if SSL_get_verify_result is relied upon for a later check of a verification result, in a use case where a user-provided verification. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required.
The client in OpenSSH before 7.2 mishandles failed cookie generation for untrusted X11 forwarding and relies on the local X11 server for access-control decisions, which allows remote X11 clients to. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Improper Authentication vulnerability could allow attackers to bypass authentication mechanisms to gain unauthorized access.
httpd in OpenBSD allows remote attackers to cause a denial of service (memory consumption) via a series of requests for a large file using an HTTP Range header. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 49.6%.
Integer overflow in the uvm_map_isavail function in uvm/uvm_map.c in OpenBSD 5.9 allows local users to cause a denial of service (kernel panic) via a crafted mmap call, which triggers the new mapping. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available.
OpenBSD 5.8 and 5.9 allows local users to cause a denial of service (NULL pointer dereference and panic) via a sysctl call with a path starting with 10,9. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available.
Remote, unauthenticated attackers who can reach an explicitly enabled OpenBSD ldapd instance can complete an LDAP Bind as another identity because delegated BSD authentication results are correlated only by the LDAP child process's client file descriptor and LDAP message ID. When a connection closes and a later connection reuses the same file descriptor and message ID, the earlier successful authentication result is delivered to the new connection, granting the attacker the other user's identity (CWE-863, incorrect authorization); the same code path also dereferences a missing connection and crashes the daemon for denial of service. Exploitation is gated by two prerequisites: ldapd must be manually enabled (it is not on by default) and configured to use delegated BSD authentication, and the identity takeover additionally requires winning a timing/resource-reuse race to land on the exact fd+message-ID pair, which is why both the CVSS 4.0 vector (AC:H/AT:P) and the independent CVSS 3.1 assessment (AC:H) rate the attack complexity as high despite PR:N. The defect is confirmed by an upstream OpenBSD source fix and errata 7.8/057 and 7.9/021; no public exploit code and no CISA KEV active-exploitation entry were identified at time of analysis.
Memory corruption in the OpenSSH client (ssh) before 10.4 lets a malicious or compromised SSH server trigger a use-after-free on the connecting client by changing its host key during a key re-exchange (rekey), potentially leading to information disclosure or code execution in the client process. Only the client side is affected; the server is not vulnerable. There is no public exploit identified at time of analysis and it is not on CISA KEV, and EPSS is low (0.25%, 16th percentile), but the flaw is fixed in OpenSSH 10.4/10.4p1.
Denial of service in OpenSSH sshd before 10.4 lets remote unauthenticated attackers exhaust server resources by driving excessive authentication attempts, because the MaxAuthTries cap was not correctly enforced for the GSSAPIAuthentication path. Only deployments that have enabled GSSAPI-based authentication are exposed, and there is no public exploit identified at time of analysis. EPSS is low (0.34%, 26th percentile) and CISA SSVC records no observed exploitation, so this is a real but non-urgent availability issue rather than a code-execution threat.
Security-control bypass in OpenSSH sshd before 10.4 causes the DisableForwarding=yes hardening directive to be silently ignored when PermitTunnel=yes is also set, so tun-device forwarding remains available despite an administrator's explicit policy to disable all forwarding. Affected operators are those who rely on DisableForwarding as a defense-in-depth restriction; the flaw lets an authenticated user establish layer-2/3 tunnels the configuration was meant to forbid. There is no public exploit identified at time of analysis, EPSS is low (0.13%, 3rd percentile), and it is not on CISA KEV.
Local privilege escalation to root in OpenBSD through 7.9 arises from a use-after-free in the System V semaphore subsystem (sys/kern/sysv_sem.c). An authenticated local user calling sys_semget() can trigger a context-switch use-after-free after tsleep(), where a freed semid_ds_kern structure is reused, enabling kernel memory corruption and full root compromise. There is no public exploit identified at time of analysis, EPSS probability is low (0.12%), and the issue is not listed in CISA KEV; the upstream fix adds reference counting (sem_ref/sem_rele) around the sleep window.
Authentication bypass in OpenBSD's sppp PAP handler (sppp_pap_input in sys/net/if_spppsubr.c) lets an adjacent attacker on a PPP link authenticate without valid credentials by supplying zero-length name/password fields, which the kernel only bounds-checked against an upper limit (AUTHMAXLEN) instead of the exact expected credential length. All OpenBSD builds before commit 076e2b1 that terminate PPP sessions with PAP authentication are affected. Publicly available exploit code exists (an Argus Systems PoC script) and a vendor fix is available, though EPSS is low (0.21%, 12th percentile) and the flaw is not in CISA KEV, so this is proof-of-concept rather than confirmed active exploitation.
Argument/command injection in OpenSSH before 10.3 lets shell metacharacters embedded in an untrusted username trigger command execution on the SSH-client host. It affects deployments that both feed an attacker-influenced username to the ssh command line and use a non-default ssh_config where %-token expansion (e.g. in ProxyCommand/LocalCommand) is enabled. There is no public exploit identified at time of analysis, EPSS is negligible (0.01%), and it is not in CISA KEV; a fixed release (10.3/10.3p1) is available.
OpenSSH before version 10.3 mishandles the authorized_keys principals option when a principals list is combined with a Certificate Authority that uses certain comma character patterns, allowing authenticated local or remote users to disclose sensitive authorization information or manipulate authentication decisions. This vulnerability affects all OpenSSH versions prior to 10.3p1 and requires authenticated access (PR:L) with non-trivial attack complexity (AC:H), resulting in partial confidentiality and integrity impact. No public exploit code or active exploitation has been identified at time of analysis.
Privilege-escalation exposure in OpenSSH before 10.3 (fixed in 10.3p1) where scp, when run by root using the legacy SCP protocol flag -O and without -p (preserve mode), may write a downloaded file with setuid or setgid bits set, contrary to user expectation. A malicious or compromised SSH server (or a man-in-the-middle on the transfer) could thereby cause an attacker-controlled binary to land on disk as a setuid/setgid-root executable, enabling local privilege escalation when it is later run. There is no public exploit identified at time of analysis, EPSS is very low (0.04%), and CISA SSVC rates exploitation as 'none' though technical impact as 'total'.
smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session, as demonstrated. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
OpenBSD through 6.6 allows local users to escalate to root because a check for LD_LIBRARY_PATH in setuid programs can be defeated by setting a very small RLIMIT_DATA resource limit. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available.
OpenSSH servers prior to 10.6 fail to enforce the 'restrict' keyword in authorized_keys against tunnel (tun/tap) forwarding, letting a user who already holds a restricted key open a forwarding tunnel that the administrator explicitly intended to block. This is a control-bypass rather than an access-control failure: the attacker must already possess a valid SSH key provisioned with 'restrict' (assessed CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N), and the flaw only matters on servers older than 10.6 where tunnel forwarding was the specific capability the keyword was relied on to deny. Impact is limited to integrity (establishing the forwarding channel) with no confidentiality or availability loss, the base score is 2.5, and no public exploit code or CISA KEV activity is identified at time of analysis.
Availability degradation in OpenSSH before 10.6 occurs because sshd and ssh fail to enforce the maximum packet length while decompressing highly compressed SSH data, allowing a peer on a connection with negotiated SSH compression to trigger excessive resource consumption. Exploitation requires compression (zlib or zlib@openssh.com) to be negotiated-often not the case on modern OpenSSH servers where compression is disabled or delayed until after authentication-and an active malicious or compromised SSH peer; the independent assessment scores this as remote, network-reachable, unauthenticated with low availability impact and no confidentiality or integrity impact. No public exploit identified at time of analysis.
ssh-keygen in OpenSSH versions before 10.6 can assign incorrect expiration timestamps to generated certificates when a Daylight Saving Time transition is mishandled, producing a bounded integrity error in the certificate's validity window. The issue is local: it requires a user to run ssh-keygen for certificate creation or signing, and it only manifests around DST changes, with slightly more pronounced effects noted for certain Antarctic time zones. With a CVSS score of 2.5 and no public exploit identified at time of analysis, this is a low-priority correctness bug rather than a remotely exploitable security flaw.
The sshd and ssh components of OpenSSH before 10.6 can be made to negotiate and use the LZ77 dictionary-coder compression scheme, a behavior the 'Crossing the Streams' research (arXiv 2609.07709) identifies as contraindicated because compression-derived information leakage can be measured from an observed session. A remote, unauthenticated attacker who can observe and influence the target connection and repeatedly sample it may recover a limited amount of confidential data, but only where the vulnerable compression mode is actually in use; integrity and availability are unaffected. This is a low-severity, low-priority issue (CVSS 3.1 base 3.7; AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N) despite being network-reachable and unauthenticated, because exploitation demands an active compression configuration, a privileged observation vantage point, and sustained measurement - no public exploit code has been identified at time of analysis and there is no confirmed active exploitation (CISA KEV).
Information disclosure in OpenSSH sshd before 10.6 can occur when GSSAPIAuthentication is enabled and multiple authentication attempts are made, allowing authentication state from a prior attempt to persist. This is a low-priority issue despite affecting a ubiquitous product, because default OpenSSH configurations set GSSAPIAuthentication to no and exploitation also requires a functioning Kerberos/GSSAPI environment. The issue carries a low severity rating, and no public exploit identified at time of analysis.
Credentials may persist in sshd after a failed GSSAPIAuthentication attempt in OpenSSH before 10.6, potentially leading to low-impact information disclosure. This issue requires GSSAPIAuthentication to be enabled (not the default), a local low-privilege attacker with an existing foothold, and user interaction; it cannot be exploited remotely or without authentication. No public exploit code has been identified, and the overall risk is low-priority.
Directory traversal in the OpenSSH sftp client before 10.6 can cause files to be written to unintended locations when a user performs a recursive copy operation against an attacker-controlled or compromised SFTP server. Exploitation requires the victim to initiate a recursive transfer such as get -r or put -r, and the malicious server supplies crafted path/filename entries containing traversal components; this is a client-side trust issue, not a flaw in an exposed sshd service. No public exploit identified at time of analysis, and the assessed CVSS 3.1 score is 4.2 with high attack complexity and user interaction required.
OpenBSD's 802.11 TKIP implementation deauthenticates all wireless clients and blocks reassociation for up to 90 seconds when an attacker within RF range sends two malformed TKIP frames separated by more than 60 seconds. The root cause is an inverted comparison operator in ieee80211_michael_mic_failure() that reverses the 60-second MIC failure countermeasure window: out-of-window failures incorrectly trigger the IEEE 802.11i countermeasure (a DoS), while in-window failures that should trigger the countermeasure are silently discarded, leaving active TKIP key-recovery attacks completely undetected. A publicly available exploit exists per the Argus Systems advisory; no KEV listing at time of analysis.
OpenSSH sshd before version 10.5 fails to enforce the `restrict` keyword in `authorized_keys` against tunnel forwarding, allowing a constrained SSH key holder to establish tun-device tunnels that the administrator explicitly intended to block. The flaw affects all OpenSSH releases prior to 10.5 and is classified as a policy-enforcement bypass with low integrity impact. No active exploitation is confirmed per SSVC (exploitation: none) and the vulnerability is absent from the CISA KEV catalog, placing this firmly in the low-urgency tier despite OpenSSH's near-ubiquitous deployment footprint.
Use-after-free (CWE-416) in OpenSSH's ssh client component affects all releases before version 10.5, triggered when a specific pair of remote-forwarding operations occur concurrently, causing access to freed realloc'd memory. A malicious or compromised SSH server could exploit this race condition against a connecting client to achieve partial information disclosure or limited memory corruption. No public exploit has been identified and CISA SSVC rates exploitation as none with partial technical impact, consistent with the moderate CVSS score of 4.8.
OpenSSH ssh-agent before version 10.5 permits remote execution of agent operations - including adding authentication tokens and using SSH keys - that were architecturally intended to be restricted to local access only. The trust boundary failure stems from a misinteraction between the agent locking mechanism and the session-bind@openssh.com extension, allowing an authenticated remote actor to cross the local/remote privilege boundary. No public exploit has been identified at time of analysis, and SSVC assessment confirms no current exploitation activity; however, the network-accessible vector and ubiquitous deployment footprint of OpenSSH make patching to 10.5 the appropriate response for any environment using agent forwarding.
OpenSSH sshd before version 10.4 fails to consistently enforce its built-in minimum authentication delay, undermining the rate-limiting defense designed to slow credential-guessing attacks against SSH services. All OpenSSH releases prior to 10.4 are affected across all platforms, enabling unauthenticated remote attackers to submit authentication attempts at a rate higher than the daemon intends to permit. No public exploit code has been identified and the vulnerability is absent from CISA KEV; however, the trivial attack complexity combined with OpenSSH's near-universal deployment footprint makes prompt patching appropriate.
OpenSSH sshd before version 10.4 silently ignores the GSSAPIStrictAcceptorCheck configuration directive when the server is integrated with Windows Active Directory, defeating a security control that administrators rely on to enforce GSSAPI acceptor name validation during Kerberos-based SSH authentication. This undocumented behavior means AD-joined SSH servers may accept GSSAPI authentications against unintended Kerberos service principals regardless of how the option is configured, yielding limited confidentiality and integrity impact. No public exploits or active exploitation have been identified; the CVSS AC:H rating reflects the specific environmental prerequisites required for exploitation.
OpenSSH's internal-sftp subsystem silently discards all command-line arguments beyond position 9, allowing authenticated SFTP users to bypass security restrictions that administrators intended to enforce via those later-positioned arguments. All OpenSSH releases before 10.4 are affected when sshd_config supplies more than nine arguments to the internal-sftp subsystem, which is a non-default but legitimate administrative pattern used for directory restriction, read-only enforcement, and umask control. No public exploit has been identified and this vulnerability is not listed in the CISA KEV catalog; however, sites relying on complex internal-sftp argument chains for access policy enforcement face a direct, silent policy bypass.
Path traversal in the scp utility of OpenSSH before 10.4 causes files to be written into the parent directory of the intended destination during remote-to-remote copy operations. The root cause is CWE-23 (Relative Path Traversal): scp fails to canonicalize or sanitize paths when relaying data between two remote hosts, allowing an attacker controlling a malicious endpoint to influence where transferred files land. No public exploit identified at time of analysis, and active exploitation has not been confirmed by CISA KEV; the CVSS AC:H and UI:R metrics significantly constrain real-world exploitability.
Path traversal in the OpenSSH sftp client before version 10.4p1 allows an attacker-controlled server to write downloaded files outside the user's intended target directory when the 'sftp server:/path .' bulk-download syntax is used. Affected are all OpenSSH deployments where users sftp from untrusted or attacker-controlled hosts, which in practice spans virtually every Linux and Unix environment. No public exploit has been identified at time of analysis and the vulnerability is not listed in CISA KEV, though the ubiquity of OpenSSH elevates aggregate exposure despite the moderate per-instance severity.
Kernel stack memory disclosure in OpenBSD's MPLS input processing exposes arbitrary kernel stack contents to unauthenticated remote attackers via crafted MPLS frames. The flaw exists in `mpls_do_error` within `sys/netmpls/mpls_input.c` (revision 1.81), where a label-stack iterator lacked an upper-bounds guard, allowing a 16-label frame with no Bottom-of-Stack bit to drive an out-of-bounds read. A publicly available exploit exists per the Argus Systems advisory; this vulnerability is not confirmed as actively exploited in the CISA KEV catalog, and the CVSS 4.0 score is 6.9.
Denial-of-service in OpenBSD slaacd and rad daemons allows local network attackers to trigger infinite loops by sending crafted ICMPv6 Neighbor Discovery packets with zero-length options, causing affected daemons to hang due to missing validation of the nd_opt_len field before arithmetic operations. OpenBSD versions through 7.8 are affected. No evidence of active exploitation has been identified.
OpenSSH before 10.3 fails to confirm connection multiplexing in proxy-mode sessions, allowing local attackers with user interaction to bypass intended access controls and potentially manipulate multiplexed connections. The vulnerability affects OpenSSH versions prior to 10.3p1 and requires local access with user interaction (UI:R) on the affected system; while the CVSS score is low (2.5) and integrity impact is limited, the omission of confirmation mechanisms in proxy-mode multiplexing creates a logic flaw that could enable unauthorized session hijacking or redirection in multi-user environments.
OpenSSH before 10.3 incorrectly interprets ECDSA algorithm specifications in PubkeyAcceptedAlgorithms and HostbasedAcceptedAlgorithms configuration options, allowing authenticated users to authenticate using unintended ECDSA variants. The vulnerability requires authenticated network access and high attack complexity, resulting in a low CVSS score of 3.1 with integrity impact but no confidentiality or availability loss. No public exploit code or active exploitation has been documented.
Vulnerability in the OpenSSH GSSAPI delta included in various Linux distributions. This vulnerability affects the GSSAPI patches added by various Linux distributions and does not affect the OpenSSH upstream project itself.
Server-side denial of service in openrsync through 0.5.0, including the copy shipped in OpenBSD through 7.8 and portable builds on other platforms, allows a client that has been accepted by the rsync server to crash the server process with a SIGSEGV. The attacker triggers the fault by specifying a block length of zero during the block-data exchange phase, a state the receiver never validates against the remaining byte count; impact is limited to availability (C:N/I:N/A:H, medium severity at CVSS 3.1 base 5.3) with no code execution or data exposure. No confirmed active exploitation (not in CISA KEV) and no public exploit identified at time of analysis, and EPSS is low at 0.28% (19th percentile), so practical risk is concentrated in servers that accept rsync sessions from untrusted clients.
In sshd in OpenSSH before 10.0, the DisableForwarding directive does not adhere to the documentation stating that it disables X11 and agent forwarding. Rated medium severity (CVSS 4.3), this vulnerability is no authentication required, low attack complexity.
In OpenBSD 7.6 before errata 006 and OpenBSD 7.5 before errata 015, traffic sent over wg(4) could result in kernel crash. Rated high severity (CVSS 7.1), this vulnerability is remotely exploitable, low attack complexity.
A flaw was found in the OpenSSH package. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. Epss exploitation probability 42.5% and no vendor patch available.
A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, no authentication required. Epss exploitation probability 60.0%.
In OpenBSD 7.4 before errata 014, vmm(4) did not restore GDTR limits properly on Intel (VMX) CPUs. Rated medium severity (CVSS 6.2), this vulnerability is low attack complexity.
In OpenBSD 7.4 before errata 006 and OpenBSD 7.3 before errata 020, httpd(8) is vulnerable to a NULL dereference when handling a malformed fastcgi request. Rated high severity (CVSS 8.7), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This NULL Pointer Dereference vulnerability could allow attackers to crash the application by dereferencing a null pointer.
In OpenBSD 7.5 before errata 009 and OpenBSD 7.4 before errata 022, exclude any '/' in readdir name validation to avoid unexpected directory traversal on untrusted file systems. Rated medium severity (CVSS 4.1), this vulnerability is low attack complexity. This Path Traversal vulnerability could allow attackers to access files and directories outside the intended path.
In OpenBSD 7.5 before errata 008 and OpenBSD 7.4 before errata 021, avoid possible mbuf double free in NFS client and server implementation, do not use uninitialized variable in error handling of NFS. Rated critical severity (CVSS 9.2), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Remote code execution in OpenSSH's sshd server (regression of CVE-2006-5051) allows unauthenticated remote attackers to exploit a signal handler race condition by failing to authenticate within the LoginGraceTime window, potentially yielding root-level code execution on glibc-based Linux systems. The flaw - widely known as 'regreSSHion' - affects numerous distributions and vendor appliances including Ubuntu 23.10/24.04, AlmaLinux 9, SonicWall SMA firmware, Arista EOS, NetApp ONTAP, and others. Publicly available exploit code exists and EPSS scores it at 48.06% (98th percentile), reflecting very high exploitation likelihood, though it is not currently listed in CISA KEV.
NFS in a BSD derived codebase, as used in OpenBSD through 7.4 and FreeBSD through 14.0-RELEASE, allows remote attackers to execute arbitrary code via a bug that is unrelated to memory corruption. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
OpenSSH through 10.0, when common types of DRAM are used, might allow row hammer attacks (for authentication bypass) because the integer value of authenticated in mm_answer_authpassword does not. Rated high severity (CVSS 7.0). No vendor patch available.
In ssh in OpenSSH before 9.6, OS command injection might occur if a user name or host name has shell metacharacters, and this name is referenced by an expansion token in certain situations. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 16.5%.
In ssh-agent in OpenSSH before 9.6, certain destination constraints can be incompletely applied. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. Public exploit code available and EPSS exploitation probability 53.6%.
OpenBSD 7.3 before errata 014 is missing an argument-count bounds check in console terminal emulation. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. This Missing Authorization vulnerability could allow attackers to access resources or perform actions without proper authorization checks.
The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if an agent is forwarded to an attacker-controlled system. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
A double free or use after free could occur after SSL_clear in OpenBSD 7.2 before errata 026 and 7.3 before errata 004, and in LibreSSL before 3.6.3 and 3.7.x before 3.7.3. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
ascii_load_sockaddr in smtpd in OpenBSD before 7.1 errata 024 and 7.2 before errata 020, and OpenSMTPD Portable before 7.0.0-portable commit f748277, can abort upon a connection from a local, scoped. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
ssh-add in OpenSSH before 9.3 adds smartcard keys to ssh-agent without the intended per-hop destination constraints. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In OpenBSD 7.2, a TCP packet with destination port 0 that matches a pf divert-to rule can crash the kernel. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Uncontrolled Resource Consumption vulnerability could allow attackers to cause denial of service by exhausting system resources.
OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required. Public exploit code available and EPSS exploitation probability 88.3%.
slaacd in OpenBSD 6.9 and 7.0 before 2022-03-22 has an integer signedness error and resultant heap-based buffer overflow triggerable by a crafted IPv6 router advertisement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
engine.c in slaacd in OpenBSD 6.9 and 7.0 before 2022-02-21 has a buffer overflow triggerable by an IPv6 router advertisement with more than seven nameservers. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
An issue was discovered in OpenSSH before 8.9. Rated low severity (CVSS 3.7), this vulnerability is remotely exploitable, no authentication required. This Improper Authentication vulnerability could allow attackers to bypass authentication mechanisms to gain unauthorized access.
sshd in OpenSSH 6.2 through 8.x before 8.8, when certain non-default configurations are used, allows privilege escalation because supplemental groups are not initialized as expected. Rated high severity (CVSS 7.0).
x509_constraints_parse_mailbox in lib/libcrypto/x509/x509_constraints.c in LibreSSL through 3.4.0 has a stack-based buffer over-read. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 14.6%.
ssh-agent in OpenSSH before 8.5 has a double free that may be relevant in a few less-common scenarios, such as unconstrained agent-socket access on a legacy operating system, or the forwarding of an. Rated high severity (CVSS 7.1), this vulnerability is remotely exploitable.
iked in OpenIKED, as used in OpenBSD through 6.7, allows authentication bypass because ca.c has the wrong logic for checking whether a public key matches. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
scp in OpenSSH through 8.3p1 allows command injection in the scp.c toremote function, as demonstrated by backtick characters in the destination argument. Rated high severity (CVSS 7.4), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
The client side in OpenSSH 5.7 through 8.4 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required.
The scp client in OpenSSH 8.2 incorrectly sends duplicate responses to the server upon a utimes system call failure, which allows a malicious unprivileged user on the remote server to overwrite. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
A vulnerability was discovered in Linux, FreeBSD, OpenBSD, MacOS, iOS, and Android that allows a malicious access point, or an adjacent user, to determine if a connected user is using a VPN, make. Rated high severity (CVSS 7.4), this vulnerability is low attack complexity. No vendor patch available.
OpenBSD 6.6, in a non-default configuration where S/Key or YubiKey authentication is enabled, allows local users to become root by leveraging membership in the auth group. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
libc in OpenBSD 6.6 allows authentication bypass via the -schallenge username, as demonstrated by smtpd, ldapd, or radiusd. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
xlock in OpenBSD 6.6 allows local users to gain the privileges of the auth group by providing a LIBGL_DRIVERS_PATH environment variable, because xenocara/lib/mesa/src/loader/loader.c mishandles. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
In OpenBSD 6.6, local users can use the su -L option to achieve any login class (often excluding root) because there is a logic error in the main function in su/su.c. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
OpenSSH 7.7 through 7.9 and 8.x before 8.1, when compiled with an experimental key type, has a pre-authentication integer overflow if a client or server is configured to use a crafted XMSS key. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available.
OpenBSD kernel version <= 6.5 can be forced to create long chains of TCP SACK holes that causes very expensive calls to tcp_sack_option() for every incoming SACK packet which can lead to a denial of. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
An issue was discovered in OpenSSH 7.9. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. Public exploit code available.
In OpenSSH 7.9, due to accepting and displaying arbitrary stderr output from the server, a malicious server (or Man-in-The-Middle attacker) can manipulate the client output, for example to use ANSI. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, no authentication required. Public exploit code available.
An issue was discovered in OpenSSH 7.9. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, no authentication required.
Remotely observable behaviour in auth-gss2.c in OpenSSH through 7.8 could be used by remote attackers to detect existence of users on a target system when GSS2 is in use. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Exposure of Sensitive Information vulnerability could allow attackers to access sensitive data that should not be disclosed.
OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed,. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
tss_alloc in sys/arch/i386/i386/gdt.c in OpenBSD 6.2 and 6.3 has a Local Denial of Service (system crash) due to incorrect I/O port access control on the i386 architecture. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
LibreSSL before 2.6.5 and 2.7.x before 2.7.4 allows a memory-cache side-channel attack on DSA and ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP. Rated medium severity (CVSS 4.7). No vendor patch available.
The int_x509_param_set_hosts function in lib/libcrypto/x509/x509_vpm.c in LibreSSL 2.7.0 before 2.7.1 does not support a certain special case of a zero name length, which causes silent omission of. Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, no authentication required.
sshd in OpenSSH before 7.4 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz,. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
The process_open function in sftp-server.c in OpenSSH before 7.6 does not properly prevent write operations in readonly mode, which allows attackers to create zero-length files. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use-after-free vulnerability in OpenSMTPD before 5.7.2 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via vectors involving req_ca_vrfy_smtp and. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 10.1%.
The OpenBSD qsort() function is recursive, and not randomized, an attacker can construct a pathological input array of N elements that causes qsort() to deterministically recurse N/4 times. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 17.0%.
A flaw exists in OpenBSD's implementation of the stack guard page that allows attackers to bypass it resulting in arbitrary code execution using setuid binaries such as /usr/bin/at. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
LibreSSL 2.5.1 to 2.5.3 lacks TLS certificate verification if SSL_get_verify_result is relied upon for a later check of a verification result, in a use case where a user-provided verification. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required.
The client in OpenSSH before 7.2 mishandles failed cookie generation for untrusted X11 forwarding and relies on the local X11 server for access-control decisions, which allows remote X11 clients to. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Improper Authentication vulnerability could allow attackers to bypass authentication mechanisms to gain unauthorized access.
httpd in OpenBSD allows remote attackers to cause a denial of service (memory consumption) via a series of requests for a large file using an HTTP Range header. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 49.6%.
Integer overflow in the uvm_map_isavail function in uvm/uvm_map.c in OpenBSD 5.9 allows local users to cause a denial of service (kernel panic) via a crafted mmap call, which triggers the new mapping. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available.
OpenBSD 5.8 and 5.9 allows local users to cause a denial of service (NULL pointer dereference and panic) via a sysctl call with a path starting with 10,9. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available.