Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Network-reachable and low-complexity once authenticated (AV:N/AC:L); a valid Kerberos principal is required (PR:L); logging in as arbitrary users yields full C:H/I:H/A:H on the host with no scope change.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
Lifecycle Timeline
2DescriptionCVE.org
A flaw was found in libssh. On servers with GSSAPIKeyExchange enabled, the gssapi-keyex path does not verify whether the authenticated Kerberos principal is authorized for the requested local user, allowing authenticated clients to log in as arbitrary users.
AnalysisAI
Privilege escalation via authentication bypass in libssh affects servers that enable GSSAPIKeyExchange, where the gssapi-keyex authentication path fails to confirm that the authenticated Kerberos principal is actually authorized for the local user account being requested. An already-authenticated client holding any valid Kerberos principal in the realm can therefore log in as an arbitrary user, including potentially privileged accounts, on Red Hat Enterprise Linux 8, 9, and 10 and Red Hat Hardened Images. No public exploit is identified at time of analysis and the issue is not listed in CISA KEV, but the CVSS of 8.8 reflects a straightforward, low-complexity abuse once a valid Kerberos credential is held.
Technical ContextAI
libssh is a widely used C library implementing the SSHv2 protocol for both client and server roles (distinct from the unrelated libssh2). The flaw lives in its GSSAPI/Kerberos key-exchange authentication method, gssapi-keyex, which is only reachable when the server is configured with GSSAPIKeyExchange enabled. Per CWE-863 (Incorrect Authorization), the code performs authentication (proving who the Kerberos principal is) but omits the authorization step that binds that principal to the specific local username requested in the SSH login. The missing check is analogous to the k5login/GSSAPI-to-local-user mapping that must gate which principals may assume which accounts; without it, any valid principal is accepted for any requested user. The affected products per CPE are Red Hat Enterprise Linux 8, 9, and 10 and Red Hat Hardened Images, all shipping the vulnerable libssh build.
RemediationAI
Apply the Red Hat libssh security update for your RHEL 8, 9, or 10 release or Red Hat Hardened Image; exact fixed version numbers are not included in the provided data, so obtain them from the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-59851 and the Bugzilla tracker at https://bugzilla.redhat.com/show_bug.cgi?id=2498184 rather than assuming a version. As the most effective compensating control until patched, disable GSSAPIKeyExchange on affected SSH servers (set GSSAPIKeyExchange no), which fully removes the vulnerable gssapi-keyex code path; the trade-off is loss of GSSAPI/Kerberos key-exchange single sign-on, so environments relying on it for passwordless Kerberos SSH will need to fall back to gssapi-with-mic or standard authentication. Where GSSAPI must remain, restrict network reachability of the SSH service to trusted management networks and tightly control which Kerberos principals are provisioned so the pool of potential abusers is minimized. Patch status: released patched version not independently confirmed from the provided references.
More in Red Hat Enterprise Linux 10
View allHeap corruption via double-free in 389-ds-base's LDAP control parsing allows an unauthenticated remote attacker to crash
Remote code execution in Cockpit's web interface allows unauthenticated attackers to execute arbitrary commands on the h
Remote code execution in Samba's printing subsystem allows remote attackers to inject arbitrary shell commands via craft
Authentication bypass in 389 Directory Server (shipped as Red Hat Directory Server 11-13 and within RHEL 6-10) lets remo
Remote code execution and privilege escalation in HPLIP (HP Linux Imaging and Printing) affects the hpcups print filter
Unauthenticated privilege escalation in FreeIPA (Red Hat Identity Management) allows a remote attacker to gain genuine a
Remote code execution in libarchive on 32-bit systems allows unauthenticated attackers to execute arbitrary code via spe
HTTP request smuggling in Undertow (the embedded web server underpinning JBoss EAP, Red Hat Data Grid, and Apache Camel
HTTP request smuggling in Red Hat Undertow allows remote unauthenticated attackers to bypass front-end security controls
Out-of-bounds read in the GnuTLS DTLS handshake reassembly logic lets remote unauthenticated attackers trigger an intege
HTTP request smuggling in Undertow allows remote unauthenticated attackers to send `\r\r\r` as a header block terminator
Local privilege escalation in Performance Co-Pilot (PCP) on Red Hat Enterprise Linux 6 through 10 and OpenShift Containe
Same weakness CWE-863 – Incorrect Authorization
View allSame technique Authentication Bypass
View allVendor StatusVendor
SUSE
Severity: Important| Product | Status |
|---|---|
| SUSE Linux Enterprise Desktop 15 SP7 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | Affected |
| SUSE Linux Enterprise Micro 5.3 | Affected |
| SUSE Linux Enterprise Micro 5.4 | Affected |
| SUSE Linux Enterprise Micro 5.5 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | Affected |
| SUSE Linux Enterprise Server 15 SP7 | Affected |
| SUSE Linux Enterprise Server 16.0 | Affected |
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| SUSE Linux Micro 6.0 | Affected |
| SUSE Linux Micro 6.1 | Affected |
| SUSE Linux Micro 6.2 | Affected |
| openSUSE Leap 16.0 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP4 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | Affected |
| SUSE Linux Enterprise Server 12 SP5 | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS Extended Security | Affected |
| SUSE Linux Enterprise Server 15 SP4 | Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP5 | Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP6 | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Affected |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Affected |
| SUSE Manager Proxy 4.3 | Affected |
| SUSE Manager Proxy LTS 4.3 | Affected |
| SUSE Manager Retail Branch Server 4.3 | Affected |
| SUSE Manager Retail Branch Server LTS 4.3 | Affected |
| SUSE Manager Server 4.3 | Affected |
| SUSE Manager Server LTS 4.3 | Affected |
| SUSE CaaS Platform 4.0 | Affected |
| SUSE Enterprise Storage 6 | Affected |
| SUSE Enterprise Storage 7 | Affected |
| SUSE Enterprise Storage 7.1 | Affected |
| SUSE Linux Enterprise Desktop 12 | Affected |
| SUSE Linux Enterprise Desktop 12 SP1 | Affected |
| SUSE Linux Enterprise Desktop 12 SP2 | Affected |
| SUSE Linux Enterprise Desktop 12 SP3 | Affected |
| SUSE Linux Enterprise Desktop 12 SP4 | Affected |
| SUSE Linux Enterprise Desktop 15 SP1 | Affected |
| SUSE Linux Enterprise Desktop 15 SP2 | Affected |
| SUSE Linux Enterprise Desktop 15 SP3 | Affected |
| SUSE Linux Enterprise Desktop 15 SP4 | Affected |
| SUSE Linux Enterprise Desktop 15 SP5 | Affected |
| SUSE Linux Enterprise Desktop 15 SP6 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | Affected |
| SUSE Linux Enterprise Micro 5.0 | Affected |
| SUSE Linux Enterprise Micro 5.1 | Affected |
| SUSE Linux Enterprise Micro 5.2 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP2 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP3 | Affected |
| SUSE Linux Enterprise Real Time 15 SP2 | Affected |
| SUSE Linux Enterprise Real Time 15 SP3 | Affected |
| SUSE Linux Enterprise Real Time 15 SP4 | Affected |
| SUSE Linux Enterprise Server 12 | Affected |
| SUSE Linux Enterprise Server 12 SP1 | Affected |
| SUSE Linux Enterprise Server 12 SP2 | Affected |
| SUSE Linux Enterprise Server 12 SP3 | Affected |
| SUSE Linux Enterprise Server 12 SP4 | Affected |
| SUSE Linux Enterprise Server 12 SP4-ESPOS | Affected |
| SUSE Linux Enterprise Server 12 SP4-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP1 | Affected |
| SUSE Linux Enterprise Server 15 SP1-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP2 | Affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP3 | Affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP2 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP3 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Affected |
| SUSE Linux Enterprise Software Development Kit 12 | Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP1 | Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP2 | Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP3 | Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP4 | Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP5 | Affected |
| SUSE Linux Enterprise Workstation Extension 12 | Affected |
| SUSE Linux Enterprise Workstation Extension 12 SP1 | Affected |
| SUSE Linux Enterprise Workstation Extension 12 SP2 | Affected |
| SUSE Linux Enterprise Workstation Extension 12 SP3 | Affected |
| SUSE Manager Proxy 4.0 | Affected |
| SUSE Manager Proxy 4.1 | Affected |
| SUSE Manager Proxy 4.2 | Affected |
| SUSE Manager Retail Branch Server 4.0 | Affected |
| SUSE Manager Retail Branch Server 4.1 | Affected |
| SUSE Manager Retail Branch Server 4.2 | Affected |
| SUSE Manager Server 4.0 | Affected |
| SUSE Manager Server 4.1 | Affected |
| SUSE Manager Server 4.2 | Affected |
| SUSE OpenStack Cloud 9 | Affected |
| SUSE OpenStack Cloud Crowbar 9 | Affected |
| openSUSE Leap 15.3 | Affected |
| openSUSE Leap 15.4 | Affected |
| openSUSE Leap 15.5 | Affected |
| openSUSE Leap 15.6 | Affected |
| openSUSE Leap Micro 5.2 | Affected |
| openSUSE Leap Micro 5.3 | Affected |
| openSUSE Leap Micro 5.4 | Affected |
| openSUSE Leap Micro 5.5 | Affected |
Share
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-46268
GHSA-x5cr-v39m-53gw