Denial of Service
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
How It Works
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions. Attackers exploit asymmetry: minimal attacker effort produces disproportionate resource consumption on the target. Application-level attacks use specially crafted inputs that trigger expensive operations—a regex engine processing malicious patterns can backtrack exponentially, or XML parsers recursively expand entities until memory exhausts. Network-level attacks flood targets with connection requests or amplify traffic through reflection, but application vulnerabilities often provide the most efficient attack surface.
The attack typically begins with reconnaissance to identify resource-intensive operations or unprotected endpoints. For algorithmic complexity attacks, adversaries craft inputs hitting worst-case performance—hash collision inputs filling hash tables with collisions, deeply nested JSON triggering recursive parsing, or pathological regex patterns like (a+)+b against strings of repeated 'a' characters. Resource exhaustion attacks open thousands of connections, upload massive files to unbounded storage, or trigger memory leaks through repeated operations. Crash-based attacks target error handling gaps: null pointer dereferences, unhandled exceptions in parsers, or assertion failures that terminate processes.
Impact
- Service unavailability preventing legitimate users from accessing applications during attack duration
- Revenue loss from downtime in e-commerce, SaaS platforms, or transaction processing systems
- Cascading failures as resource exhaustion spreads to dependent services or database connections pool out
- SLA violations triggering financial penalties and damaging customer trust
- Security team distraction providing cover for data exfiltration or intrusion attempts running concurrently
Real-World Examples
CVE-2018-1000544 in Ruby's WEBrick server allowed ReDoS through malicious HTTP headers containing specially crafted patterns that caused the regex engine to backtrack exponentially, freezing request processing threads. A single attacker could saturate all available workers.
Cloudflare experienced a global outage in 2019 when a single WAF rule containing an unoptimized regex hit pathological cases on legitimate traffic spikes. The .*(?:.*=.*)* pattern exhibited catastrophic backtracking, consuming CPU cycles across their edge network until the rule was disabled.
CVE-2013-1664 demonstrated XML bomb vulnerabilities in Python's XML libraries. Attackers uploaded XML documents with nested entity definitions-each entity expanding to ten copies of the previous level. A 1KB upload could expand to gigabytes in memory during parsing, crashing applications instantly.
Mitigation
- Strict input validation enforcing size limits, complexity bounds, and nesting depth restrictions before processing
- Request rate limiting per IP address, API key, or user session with exponential backoff
- Timeout enforcement terminating operations exceeding reasonable execution windows (typically 1-5 seconds)
- Resource quotas limiting memory allocation, CPU time, and connection counts per request or tenant
- Regex complexity analysis using linear-time algorithms or sanitizing patterns to eliminate backtracking
- Circuit breakers automatically rejecting requests when error rates or latency thresholds indicate degradation
- Load balancing and autoscaling distributing traffic across instances with automatic capacity expansion
Recent CVEs (5444)
Incus versions prior to 6.23.0 allow local authenticated attackers to manipulate temporary screenshot files via predictable /tmp paths and symlink attacks, potentially truncating and altering permissions of arbitrary files on systems with disabled symlink protection (rare), leading to denial of service or local privilege escalation. The vulnerability requires local access and authenticated user privileges but is particularly dangerous on systems without kernel-level symlink protections enabled. An exploit proof-of-concept exists, and the vendor has released patched version 6.23.0 to address the issue.
TigerVNC x0vncserver versions prior to 1.16.2 expose screen contents to unauthorized local users through incorrect file permissions in Image.cxx, enabling information disclosure, screen manipulation, or denial of service. The vulnerability has CVSS 8.5 (High) with local attack vector requiring no privileges or user interaction, and scope change indicating potential impact beyond the vulnerable component. No public exploit identified at time of analysis, though technical details are available via GitHub commit and mailing list disclosure.
Ella Core crashes when processing NAS Authentication Response and Authentication Failure messages with missing Information Elements, enabling unauthenticated attackers on the adjacent network to trigger denial of service affecting all connected subscribers. The vulnerability stems from a null pointer dereference in message handling logic (CWE-476) and carries a CVSS 6.5 score reflecting high availability impact with low attack complexity. Vendor-released patch available via GitHub release v1.7.0.
Ella Core's AMF control plane deadlocks in the SCTP notification handler when processing malformed or stale radio entries, allowing unauthenticated attackers with N2 interface access to hang the entire Access and Mobility Function until manual process restart, completely denying service to all subscribers. The vulnerability (CVSS 6.5, CWE-833 deadlock) stems from improper synchronization in radio cleanup logic combined with stale-entry scanning, and patches are available in version 1.7.0 and later.
Ella Core suffers a null pointer dereference vulnerability in its NGAP LocationReport message handler that causes the process to panic and crash, enabling unauthenticated network-adjacent attackers to trigger denial of service affecting all connected mobile subscribers. The vulnerability (CVE-2026-33903, CVSS 6.5) stems from missing input validation guards and has a vendor-released patch available in version 1.7.0; no public exploit code or active exploitation has been identified at time of analysis.
The node-forge cryptographic library for Node.js suffers from a complete Denial of Service condition when the BigInteger.modInverse() function receives zero as input, causing an infinite loop that consumes 100% CPU and blocks the event loop indefinitely. All versions of node-forge (npm package) are affected, impacting applications that process untrusted cryptographic parameters through DSA/ECDSA signature verification or custom modular arithmetic operations. CVSS 7.5 (High severity) reflects network-reachable, unauthenticated exploitation with no user interaction required. A working proof-of-concept exists demonstrating the vulnerability triggers within 5 seconds. Vendor patch is available via GitHub commit 9bb8d67b99d17e4ebb5fd7596cd699e11f25d023.
TSPortal versions prior to 34 contain an uncontrolled resource creation vulnerability that allows authenticated attackers to generate arbitrary user database records through validation logic abuse, resulting in potential denial of service via uncontrolled database growth. The flaw exists in Miraheze's Trust and Safety management platform (cpe:2.3:a:miraheze:tsportal) and requires low-privilege authenticated access to exploit. Vendor-released patch available in version 34; no public exploit identified at time of analysis.
libssh attempts to open arbitrary files during configuration parsing, allowing local attackers with limited privileges to trigger a denial of service by forcing access to dangerous files such as block devices or large system files. The vulnerability affects Red Hat Enterprise Linux versions 6, 7, 8, 9, and 10, as well as Red Hat OpenShift Container Platform 4, and requires local access with low privileges to exploit. No public exploit code or active exploitation has been confirmed at the time of analysis.
libssh's match_pattern() function is vulnerable to ReDoS (Regular Expression Denial of Service) attacks when processing maliciously crafted hostnames in client configuration or known_hosts files, allowing local attackers with limited privileges and user interaction to trigger inefficient regex backtracking that exhausts system resources and causes client-side timeouts. The vulnerability affects Red Hat Enterprise Linux 6-10 and OpenShift Container Platform 4, with CVSS 2.2 reflecting low severity due to local attack vector and high complexity requirements, though the denial of service impact warrants attention in environments where SSH client availability is critical.
Libssh versions used across Red Hat Enterprise Linux 6-10 and OpenShift Container Platform 4 are vulnerable to a null pointer dereference when processing malformed 'longname' fields in SFTP SSH_FXP_NAME messages, allowing unauthenticated remote attackers to trigger denial of service through application crashes. The attack requires user interaction and high attack complexity (CVSS 3.1, CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L) but affects a widely deployed SSH library; no public exploit identified at time of analysis.
Grafana MSSQL data source plugin versions across multiple release branches contain a logic flaw enabling low-privileged Viewer users to bypass API restrictions and trigger catastrophic out-of-memory exhaustion, resulting in host container denial of service. The vulnerability affects Grafana OSS versions 11.6.0 through 12.4.0 across multiple patch branches (11.6.14+security-01, 12.1.10+security-01, 12.2.8+security-01, 12.3.6+security-01, and 12.4.2 or later) and requires only network access and valid low-privileged credentials to exploit; no public exploit code or active exploitation has been confirmed at time of analysis.
p11-kit remote token handling fails to validate NULL derive mechanism parameters in C_DeriveKey operations, allowing unauthenticated remote attackers to trigger NULL pointer dereferences and undefined memory access in the RPC client layer. This denial-of-service vulnerability affects Red Hat Enterprise Linux versions 6 through 10 and OpenShift Container Platform 4, with a CVSS score of 5.3 reflecting moderate availability impact. No public exploit identified at time of analysis.
GIMP's PSD file parser crashes when processing specially crafted Photoshop documents due to improper null-termination in the fread_pascal_string function, allowing local authenticated users to trigger a denial of service. The vulnerability affects GIMP across Red Hat Enterprise Linux 7, 8, and 9, as well as multiple Debian and Ubuntu releases tracked by their respective security teams. While the CVSS score is low (2.8), the widespread distribution across major Linux vendors and confirmed advisory issuance from Red Hat, Debian, and SUSE indicates this merits coordinated patching despite limited exploitability constraints.
A security vulnerability in A flaw (CVSS 4.3). Remediation should follow standard vulnerability management procedures.
GIMP's PSP file parser fails to validate 32-bit length values in the read_creator_block() function, allowing local attackers to trigger integer overflow and heap buffer overflow via specially crafted PSP image files, resulting in application-level denial of service. Red Hat Enterprise Linux versions 6-9, Ubuntu (7 releases), Debian (9 releases), and SUSE are affected. No public exploit code or active exploitation has been identified at the time of analysis, though the vulnerability has been assigned ENISA EUVD ID EUVD-2026-16340 and tracked across major Linux distributions.
The antchfx/xpath Go library prior to version 1.3.6 contains a denial-of-service vulnerability in the logicalQuery.Select function where Boolean XPath expressions that evaluate to true (such as '1=1' or 'true()') trigger an infinite loop, consuming 100% CPU resources. Remote attackers can exploit this via top-level XPath selectors without authentication, potentially disrupting any application that uses this library to process untrusted XPath queries. Upstream fix is available in commit afd4762cc342af56345a3fb4002a59281fcab494, with no public exploit code identified at time of analysis.
The jsonparser library for Go fails to validate slice offsets when processing malformed JSON, enabling remote denial of service through crafted input that triggers negative array indices and runtime panics. The GitHub buger/jsonparser project across all versions is affected. Attackers can send specially crafted JSON payloads to applications using vulnerable versions, causing immediate service termination without requiring authentication or user interaction.
Truncated msgpack fixext format data (codes 0xd4-0xd8) decoded by shamaton/msgpack library versions across v1, v2, and v3 fail to validate input buffer boundaries, triggering out-of-bounds memory reads and runtime panics that enable denial of service. Remote attackers can craft malformed msgpack payloads to crash applications using affected library versions without requiring authentication or user interaction.
libsoup's SoupServer contains a use-after-free vulnerability in the soup_server_disconnect() function that prematurely frees connection objects while TLS handshakes are pending, allowing remote unauthenticated attackers to trigger a server crash via denial of service when a handshake completes after memory deallocation. The vulnerability affects Red Hat Enterprise Linux versions 6, 7, 8, 9, and 10, as well as Ubuntu and Debian distributions across multiple releases. No public exploit code or active exploitation has been confirmed at the time of analysis.
Tandoor Recipes versions prior to 2.6.0 allow authenticated remote attackers to cause denial of service by injecting URL parameters into the USDA FoodData Central search endpoint through improper URL encoding of the query parameter, enabling API key override and server crashes via malformed requests. Publicly available exploit code exists, and a vendor-released patch is available in version 2.6.0.
path-to-regexp versions prior to 8.4.0 are vulnerable to Regular Expression Denial of Service (ReDoS) when processing multiple wildcard parameters combined with path parameters in specific configurations. Unauthenticated remote attackers can craft malicious path patterns containing multiple wildcards (not at the end) to trigger catastrophic regex backtracking, causing denial of service against applications using the affected library. No public exploit code or active exploitation has been confirmed at time of analysis.
The path-to-regexp library versions 8.0.0 through 8.3.0 suffer from catastrophic regular expression denial of service via exponential regex generation when route patterns contain multiple sequential optional groups in curly-brace syntax. Remote unauthenticated attackers can trigger resource exhaustion by submitting crafted route patterns, causing application-level denial of service with CVSS 7.5 (High severity). No public exploit identified at time of analysis, and the vendor has released version 8.4.0 to address the issue.
Prototype pollution in convict npm package version 6.2.4 allows attackers to bypass previous security fixes and pollute Object.prototype through crafted input that manipulates String.prototype.startsWith. The vulnerability affects applications processing untrusted input via convict.set() and can lead to authentication bypass, denial of service, or remote code execution if polluted properties reach dangerous sinks like eval or child_process. A working proof-of-concept exploit demonstrating the bypass technique exists in the advisory.
Netty HTTP/2 servers can be rendered unresponsive by remote attackers flooding CONTINUATION frames with zero-byte payloads, bypassing existing header size limits and exhausting CPU resources. The affected package is io.netty:netty-codec-http2 (tracked via GitHub Security Advisory GHSA-w9fj-cfpg-grvv). Authentication requirements are not confirmed from available data. No public exploit identified at time of analysis, though the technical details provided in the advisory enable straightforward reproduction. The low bandwidth requirement for this CPU-based denial of service makes it highly practical for disrupting services at scale.
Brace-expansion library versions prior to 5.0.5 allow unauthenticated remote attackers to cause denial of service through resource exhaustion by supplying brace expansion patterns with zero step values (e.g., {1..2..0}), triggering an infinite loop that consumes gigabytes of memory and hangs the process for seconds. The vulnerability affects any application passing untrusted input to the expand() function, including glob/minimatch-based tools consuming CLI arguments or configuration files, and requires only 10 bytes of malicious input to trigger.
Stirling-PDF versions 2.1.5 through 2.5.1 are vulnerable to resource exhaustion denial of service through the watermark API endpoint, where authenticated users can supply extreme values for fontSize and widthSpacer parameters to crash the server. A proof-of-concept exists according to SSVC data, and the vendor has released patched version 2.5.2 to resolve the issue.
EVerest charging software stack versions prior to 2026.02.0 contain a use-after-free vulnerability in the ISO15118_chargerImpl::handle_session_setup function that crashes the EVSE process when session setup commands are issued after ISO15118 initialization failure. Remote attackers with MQTT access can trigger this denial of service condition by sending a crafted session_setup command, causing the process to reference freed memory (v2g_ctx). A vendor-released patch is available in version 2026.02.0.
Mattermost server versions 10.11.x through 11.4.x fail to validate decompressed archive entry sizes during ZIP file extraction, allowing authenticated users with file upload permissions to trigger denial of service by uploading crafted zip bombs that exhaust server memory. The vulnerability affects Mattermost 10.11.0-10.11.11, 11.2.0-11.2.3, 11.3.0-11.3.1, and 11.4.0, with CVSS 6.5 (medium) reflecting the requirement for prior authentication and limited scope (availability impact only). No public exploit identified at time of analysis, though the attack vector is network-accessible and requires low complexity once an attacker has valid upload credentials.
Mattermost Plugins versions 11.4 and earlier fail to validate incoming request sizes on webhook endpoints, allowing authenticated attackers to trigger denial of service by sending oversized requests. The vulnerability affects multiple Mattermost release branches (10.x, 11.0.x, 11.1.x, 11.3.x) and has been assigned CVSS 4.9 (medium severity) with no public exploit identified at time of analysis. While exploitability requires high-privilege authentication and manual intervention, the lack of request size enforcement on webhooks represents a fundamental input validation gap that could disrupt service availability in production environments.
Catastrophic backtracking in path-to-regexp versions prior to 0.1.13 enables remote denial of service attacks through specially crafted URLs containing three or more parameters within a single route segment separated by non-period characters. The vulnerability stems from insufficient backtrack protection in regex generation for routes like /:a-:b-:c, allowing unauthenticated attackers to trigger exponential computation times. SSVC framework confirms the vulnerability is automatable with partial technical impact, though no public exploit is identified at time of analysis.
Polkit's polkit-agent-helper-1 setuid binary fails to bound input length on stdin, allowing local authenticated users to trigger out-of-memory conditions and deny system availability. An attacker with local login privileges can supply excessively long input to exhaust memory resources, causing a system-wide denial of service. No public exploit code or active exploitation has been confirmed at the time of analysis.
Remote denial-of-service in Siemens CPCI85 Central Processing/Communication and RTUM85 RTU Base (versions below V26.10) allows adjacent network attackers to exhaust system resources via high-volume requests, forcing device reset or reboot to restore parameterization functionality. No public exploit identified at time of analysis. CVSS 7.1 (High) with adjacent network access vector and no privileges required indicates moderate real-world risk for industrial environments where these RTU and control processing devices operate.
HCL Aftermarket DPC version 1.0.0 is vulnerable to excessive spamming that consumes server bandwidth and processing resources, potentially causing denial of service to legitimate users. The vulnerability requires user interaction (UI:R per CVSS vector) and is remotely exploitable without authentication, resulting in partial availability impact. No public exploit code or active exploitation has been identified at time of analysis, though the low barrier to exploitation (AC:L) makes this a practical attack vector for resource exhaustion.
GIMP's PCX file loader contains a heap buffer over-read vulnerability caused by an off-by-one error (CWE-193) that allows local attackers to trigger out-of-bounds memory disclosure and application crashes by opening specially crafted PCX images. Red Hat Enterprise Linux versions 6 through 9 are affected. The vulnerability requires user interaction to open a malicious file but carries a CVSS score of 6.1 with high availability impact; no public exploit code or active exploitation has been identified at the time of analysis.
Linux kernel ICMP tag validation routines fail to check for NULL protocol handler pointers before dereferencing them, causing kernel panics in softirq context when processing fragmentation-needed errors with unregistered protocol numbers and ip_no_pmtu_disc hardened mode enabled. The vulnerability affects multiple Linux kernel versions across stable branches (6.1, 6.6, 6.12, 6.18, 6.19, and 7.0-rc5), with an EPSS score of 0.02% (7th percentile) indicating low real-world exploitation probability. No public exploit code or active exploitation has been confirmed; the fix requires adding a NULL pointer check in icmp_tag_validation() before accessing icmp_strict_tag_validation.
Linux kernel nfnetlink_osf module fails to validate TCP option lengths in OS fingerprint definitions, allowing null pointer dereference and out-of-bounds memory reads when processing packets with malformed or missing TCP options. The vulnerability affects Linux kernel versions across multiple stable branches (6.1.x through 6.19.x and 7.0-rc5), with EPSS score of 0.02% indicating low practical exploitation probability despite the memory safety issue. No public exploit code or active exploitation has been reported.
Linux kernel mac80211 mesh networking crashes on NULL pointer dereference when processing Channel Switch Announcement (CSA) action frames lacking Mesh Configuration IE, allowing adjacent WiFi attackers to trigger kernel panic (DoS) via crafted frames. Affects multiple stable kernel versions (6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10, 7.0-rc5 and earlier); EPSS exploitation probability is 0.02% (low), no public exploit identified, and upstream fixes are available across all affected release branches.
NVMe/TCP targets are vulnerable to unauthenticated denial of service when a remote attacker sends a CONNECT command with an invalid CNTLID, triggering a kernel panic on the exposed system. The vulnerability exploits a null pointer dereference that allows any network-accessible attacker to crash the target without authentication. No patch is currently available for this high-severity flaw.
Uncontrolled recursion in the Markdown Handler component of Orc discount up to version 3.0.1.2 causes denial of service through malformed deeply-nested blockquote inputs, affecting local users who process untrusted markdown files. Public exploit code exists for this vulnerability, and no patch is currently available. The issue requires local access and low privileges to trigger but can crash the application.
Squid versions prior to 7.5 contain a heap use-after-free vulnerability (CWE-416) in ICP (Internet Cache Protocol) traffic handling that enables remote attackers to reliably trigger denial of service against affected proxy services. The vulnerability affects any Squid deployment with ICP support explicitly enabled via non-zero icp_port configuration, and cannot be mitigated through access control rules alone. A patch is available in version 7.5, and the vulnerability has been confirmed across multiple Debian releases and SUSE distributions.
Squid proxy versions prior to 7.5 contain use-after-free and premature resource release vulnerabilities in ICP (Internet Cache Protocol) traffic handling that enable reliable, repeatable denial of service attacks. Remote attackers can exploit these memory safety bugs to crash the Squid service by sending specially crafted ICP packets, affecting deployments that have explicitly enabled ICP support via non-zero icp_port configuration. While no CVSS score or EPSS value is currently published, the vulnerability is confirmed by vendor advisory and includes a public patch commit, indicating moderate to high real-world risk for affected deployments.
Kirby CMS versions through 5.1.4 allow authenticated editors to trigger a persistent denial of service by uploading malformed images that bypass getimagesize() validation, causing fatal TypeErrors during metadata or thumbnail processing. A proof-of-concept exists and the vulnerability is automatable post-authentication, though no CISA KEV confirmation is evident. The impact is availability degradation affecting CMS operations for all users.
picomatch, a widely-used Node.js glob pattern matching library, contains a Regular Expression Denial of Service (ReDoS) vulnerability when processing crafted extglob patterns such as '+(a|aa)' or nested patterns like '+(+(a))'. The vulnerability affects picomatch versions prior to 4.0.4, 3.0.2, and 2.3.2 (tracked via CPE pkg:npm/picomatch) and allows unauthenticated remote attackers to cause multi-second event-loop blocking with relatively short inputs, resulting in application-wide denial of service. Patches are available from the vendor, and while no KEV listing or EPSS score is provided in the data, the CVSS score of 7.5 (High) reflects the network-accessible, low-complexity attack vector requiring no privileges or user interaction.
Rails Active Storage's proxy controller fails to limit the number of byte ranges accepted in HTTP Range headers, allowing attackers to craft requests with thousands of small ranges that consume disproportionate CPU resources compared to legitimate file requests. This denial-of-service vulnerability affects Ruby on Rails applications using the ActiveStorage library (pkg:rubygems/activestorage). An attacker can trigger resource exhaustion by sending Range requests with many byte ranges, potentially rendering the application unavailable to legitimate users.
This vulnerability in pypdf allows an attacker to craft a malicious PDF file that triggers an infinite loop when processed in non-strict mode, resulting in a denial of service condition. The affected product is pypdf (Python package available via pip), and the vulnerability has been patched in version 6.9.2. While no CVSS score or EPSS data is currently available, the vulnerability is classified as a denial of service issue stemming from improper loop handling (CWE-835: Infinite Loop).
LiquidJS template engine version 10.24.0 and earlier contains a denial-of-service vulnerability in the replace_first filter that enables 625,000:1 memory amplification by exploiting JavaScript's $& backreference pattern. The memoryLimit security control is bypassed because only input strings are charged while exponentially amplified outputs (up to 312.5 MB from 1 byte input) remain unaccounted. Demonstrated proof-of-concept shows 20 concurrent requests cause complete service unavailability for 29 seconds with legitimate user requests delayed by 10.9 seconds. A patch is available via GitHub commit 35d523026345d80458df24c72e653db78b5d061d.
LiquidJS versions 10.24.x and earlier contain a memory limit bypass vulnerability that allows unauthenticated attackers to crash Node.js processes through a single malicious template. By exploiting reverse range expressions to drive the memory counter negative, attackers can allocate unlimited memory and trigger a V8 Fatal error that terminates the entire process, causing complete denial of service. A detailed proof-of-concept exploit is publicly available demonstrating the full attack chain from bypass to process crash.
A critical pre-authentication denial of service vulnerability in nats-server allows an unauthenticated remote attacker to crash the entire server process by sending a single malicious 15-byte WebSocket frame. The vulnerability affects nats-server versions 2.2.0 through 2.11.13 and 2.12.0 through 2.12.4 when WebSocket listeners are enabled. A working proof-of-concept exploit in Go has been publicly disclosed by security researcher Mistz1, demonstrating that a single TCP connection can bring down the entire NATS deployment including all connected clients, JetStream streams, and cluster routes.
GitLab CE/EE contains a denial of service vulnerability in webhook configuration processing that allows authenticated users to consume excessive server resources, affecting versions 16.10 through 18.10.0. An attacker with valid GitLab credentials can trigger this issue by submitting specially crafted webhook configuration inputs, resulting in application unavailability. A proof-of-concept exploit is publicly available via HackerOne, and patches are available for affected versions.
GitLab CE/EE contains a denial of service vulnerability in CI-related input handling that allows authenticated users to consume excessive server resources, potentially rendering the service unavailable. Versions 13.7 through 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1 are affected across all GitLab installations. A publicly available proof-of-concept exists from HackerOne (report 3418149), though CISA has not flagged this for active exploitation in the wild, and the SSVC framework indicates no evidence of current weaponization despite automatable characteristics being unavailable.
GitLab CE/EE contains a denial of service vulnerability in GraphQL request processing due to improper input validation (CWE-407). All versions from 18.5 through 18.8.6, 18.9 through 18.9.2, and 18.10 before 18.10.1 are affected. An unauthenticated attacker can remotely exploit this with low complexity to render GitLab instances unresponsive, and a public proof-of-concept exploit is available via HackerOne report 3597342.
Mattermost fails to properly sanitize external SVG rendering in link embeds, allowing unauthenticated users to trigger denial-of-service conditions in both web and desktop applications. An attacker can create a malicious GitHub issue or pull request containing a crafted external SVG that crashes the Mattermost webapp and desktop client when the link is embedded. This vulnerability affects Mattermost versions 11.4.0 and below, 11.3.1 and below, 11.2.3 and below, and 10.11.11 and below, with a CVSS score of 4.3 indicating low-to-moderate severity focused on availability impact rather than confidentiality or integrity.
Mattermost versions 11.4.0, 11.3.x through 11.3.1, 11.2.x through 11.2.3, and 10.11.x through 10.11.11 lack proper rate limiting on login endpoints, allowing unauthenticated attackers to trigger denial of service through HTTP/2 single packet attacks delivering 100+ parallel login requests. This causes server crashes and forced restarts. While the CVSS score of 4.3 is moderate and requires low attack complexity over the network, the vulnerability enables complete service disruption without authentication.
Improper validation of malformed SCP requests in Cisco IOS XE Software allows authenticated local attackers to trigger unexpected device reloads and cause service disruption. An attacker with low privileges can exploit this vulnerability by sending a crafted SSH command to the SCP server component. No patch is currently available for this denial of service vulnerability.
Insufficient privilege validation on the start maintenance command in Cisco IOS XE Software enables authenticated local attackers to trigger a denial of service by placing devices into maintenance mode, which disables network interfaces. Low-privileged users can exploit this via CLI access without administrative credentials. Device recovery requires administrator intervention using the stop maintenance command.
Memory exhaustion in Cisco IOS XE and Apple devices via improper TLS resource handling allows adjacent attackers to trigger denial of service by repeatedly initiating failed authentication or manipulating TLS connections. An unauthenticated attacker can exploit this by resetting TLS sessions or abusing EAP authentication mechanisms to deplete device memory without requiring network access from the internet. Successful exploitation renders affected devices unresponsive, with no patch currently available.
HTTP Server input validation failures in Cisco IOS and IOS XE Release 3E enable authenticated remote attackers to trigger device reloads via malformed requests, causing denial of service. An attacker with valid credentials can exploit improper input handling to exhaust watchdog timers and force unexpected system restarts. No patch is currently available for this vulnerability affecting Cisco and Apple products.
A denial of service vulnerability in the Internet Key Exchange (CVSS 8.6). High severity vulnerability requiring prompt remediation.
This is a denial of service vulnerability in Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family caused by improper handling of malformed CAPWAP (Control and Provisioning of Wireless Access Points) packets. The vulnerability affects multiple versions of Cisco IOS XE Software in the 17.14.x through 17.18.x release trains. An unauthenticated remote attacker can exploit this to cause the wireless controller to reload unexpectedly, resulting in complete network disruption with a high severity CVSS score of 8.6.
Improper BOOTP packet handling in Cisco IOS XE Software on Catalyst 9000 Series Switches allows unauthenticated remote attackers to trigger VLAN leakage and cause device unavailability through resource exhaustion. An attacker can send crafted BOOTP requests to forward packets across VLANs, leading to high CPU utilization that renders the switch unreachable and unable to process traffic. No patch is currently available for this denial-of-service vulnerability.
Nanoleaf Lines firmware versions prior to 12.3.6 lack authentication controls on firmware file upload endpoints, allowing remote unauthenticated attackers to upload arbitrary files to the device. This vulnerability enables denial-of-service attacks through storage resource exhaustion and potential firmware tampering without requiring valid credentials or user interaction. The vulnerability has a CVSS score of 6.5 (Medium) with network-based attack vector and low complexity, and is tagged with denial-of-service impact indicators in CISA reporting.
BIND 9 DNS server crashes when processing specially crafted TSIG-authenticated queries containing TKEY records, affecting versions 9.20.0-9.20.20, 9.21.0-9.21.19, and 9.20.9-S1-9.20.20-S1 on Ubuntu, SUSE, and Debian systems. An authenticated attacker with a valid TSIG key can trigger a denial of service by sending a malformed query, disrupting DNS resolution services. A patch is available for affected installations.
A race condition exists in the Linux kernel's AF_UNIX socket implementation where the garbage collector (GC) can incorrectly purge receive queues of alive sockets when MSG_PEEK operations occur concurrently with socket closure. The vulnerability affects all Linux kernel versions and allows local attackers with socket access to cause information disclosure or denial of service by triggering the race condition between MSG_PEEK, socket closure, and GC execution. A proof-of-concept demonstrating the issue has been publicly reported by Igor Ushakov, and patches are available in the stable kernel tree.
A buffer overflow vulnerability exists in the Linux kernel's dma_map_sg tracepoint that can be triggered when tracing large scatter-gather lists, particularly with devices like virtio-gpu that create large DRM buffers exceeding 1000 entries. The vulnerability affects all Linux kernel versions prior to the fix and can cause perf buffer overflow warnings and potential kernel instability when dynamic array allocations exceed PERF_MAX_TRACE_SIZE (8192 bytes). While this is a kernel-level issue requiring local access to trigger tracing functionality, it poses a denial-of-service risk and memory safety concern for systems using performance tracing on workloads with large scatter-gather operations.
A metadata validation vulnerability in the Linux kernel's Squashfs filesystem implementation allows out-of-bounds memory access when processing corrupted or malicious filesystem images. Specifically, a negative metadata block offset derived from a corrupted index lookup table is passed to squashfs_copy_data without bounds checking, causing a general protection fault. Any Linux system mounting an untrusted Squashfs image is affected, potentially enabling denial of service or information disclosure attacks, though no active exploitation in the wild is currently documented.
A buffer management vulnerability exists in the Linux kernel's Google Virtual Ethernet (GVE) driver within the gve_tx_clean_pending_packets() function when operating in DQ-QPL (Descriptor Queue with Queue Pair Lists) mode. The function incorrectly interprets buffer IDs as DMA addresses and attempts to unmap memory using the wrong cleanup path, causing out-of-bounds array access and potential memory corruption. This affects Linux kernel versions across multiple stable branches and can be triggered during network device reset operations, potentially leading to kernel crashes or memory safety violations.
A memory management vulnerability in the Linux kernel's netfilter nf_tables subsystem can be triggered through fault injection during set flush operations, causing a kernel warning splat when memory allocation fails under GFP_KERNEL conditions. This vulnerability affects Linux kernel versions across distributions and is exploitable by local attackers with network namespace capabilities, potentially leading to kernel warnings and denial of service through memory exhaustion attacks. While no CVSS score or active exploitation in the wild has been reported, the vulnerability was discovered through syzbot fuzzing with fault injection, indicating it requires specific conditions to trigger but represents a real kernel stability issue that has been patched.
This vulnerability affects multiple Linux kernel HID (Human Interface Device) drivers that lack proper validation checks when processing raw event callbacks from unclaimed HID devices. An attacker could connect a malicious or broken HID device to trigger a NULL pointer dereference in affected drivers, causing a kernel crash and denial of service. The vulnerability was identified as a gap in security hardening following a similar fix applied to the appleir driver, and patches are available across multiple stable kernel branches.
A NULL pointer dereference vulnerability exists in the Linux kernel's bridge networking module when IPv6 is disabled via the 'ipv6.disable=1' boot parameter. When Neighbor Discovery (ND) suppression is enabled on a bridge, an ICMPv6 packet reaching the bridge causes the kernel to dereference a NULL pointer in the nd_tbl structure, resulting in a kernel panic and denial of service. This affects all Linux kernel versions with this code path, and while no CVSS score or EPSS data is currently available, the vulnerability is readily triggered through network packet receipt on systems with specific boot configurations.
A reference counting vulnerability in the Linux kernel's tracing subsystem causes a WARN_ON to trigger when a process forks and both parent and child processes exit, particularly when the application calls madvise(MADV_DOFORK) to enable VMA copy-on-fork behavior. The vulnerability affects all Linux kernel versions with the vulnerable tracing_buffers_mmap code and allows local attackers to cause a kernel warning that may lead to denial of service or information disclosure through the kernel warning itself. While not currently listed in KEV or known to be actively exploited, the vulnerability has been patched in stable kernel branches as indicated by four separate commit references.
A divide-by-zero vulnerability exists in the Linux kernel's ETS (Enhanced Transmission Selection) qdisc offload implementation that can crash the kernel when processing malformed traffic scheduling configurations. The vulnerability affects all Linux kernel versions with the ETS scheduler module enabled, and a local privileged user (or attacker with CAP_NET_ADMIN capability) can trigger a kernel panic by crafting specific netlink messages via the tc (traffic control) utility. While no public exploit code has been confirmed in the wild, the condition is easily reproducible and results in immediate kernel crash, making this a high-priority local denial-of-service vector.
A memory buffer management vulnerability exists in the Linux kernel's ice network driver XDP (eXpress Data Path) implementation, specifically in how it calculates fragment buffer sizes for receive queues. The vulnerability affects Linux kernel versions with the vulnerable ice driver code path and can be triggered through XDP operations that attempt to grow multi-buffer packet tails, potentially causing kernel panics or denial of service. An attacker with the ability to load and execute XDP programs can exploit this by crafting specific packet sizes and offset values to trigger the panic condition, as demonstrated by the XSK_UMEM__MAX_FRAME_SIZE test case, though real-world exploitation requires local access to load XDP programs.
A resource management vulnerability exists in the Linux kernel's nvmet-fcloop NVMe-FC loopback driver where the lsrsp (LS response) callback is invoked without proper validation of the remote port state, potentially leading to use-after-free or double-free conditions. This affects Linux kernel implementations using nvmet-fcloop for NVMe-FC transport emulation across all versions prior to the patch commits (f30b95159a53e72529a9ca1667f11cd1970240a7, 31d3817bcd9e192b30abe3cf4b68f69d48864dd2, dd677d0598387ea623820ab2bd0e029c377445a3). An attacker with local kernel-level access or ability to trigger abnormal nvmet-fcloop state transitions could potentially cause information disclosure or denial of service through memory corruption.
A vulnerability in the Linux kernel's Transparent Huge Pages (THP) subsystem incorrectly enables THP for files on anonymous inodes (such as guest_memfd and secretmem), which were not designed to support large folios. This can trigger kernel crashes via memory copy operations on unmapped memory in secretmem, or WARN_ON conditions in guest_memfd fault handlers. The vulnerability affects Linux kernel versions across multiple stable branches and requires a kernel patch to remediate; while not known to be actively exploited in the wild, the condition can be triggered locally by unprivileged users through madvise() syscalls.
This vulnerability is a preemption context violation in the Linux kernel's block I/O tracing subsystem where tracing_record_cmdline() unsafely uses __this_cpu_read() and __this_cpu_write() operations from preemptible context. The Linux kernel in versions supporting blktrace (affected via CPE cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*) is vulnerable, allowing potential information disclosure or denial of service when block tracing is enabled and block I/O operations occur from user-space processes. This is not actively exploited in the wild (no KEV status), but the vulnerability has functional proof of concept through blktests/blktrace/002, making it a moderate priority for kernel maintainers and distributions shipping PREEMPT(full) configurations.
The Linux kernel's Realtek WiFi driver (rsi) incorrectly defaults to returning -EOPNOTSUPP error code in the rsi_mac80211_config function, which triggers a WARN_ON condition in ieee80211_hw_conf_init and deviates from expected driver behavior. This affects Linux kernel versions across multiple stable branches where the rsi WiFi driver is compiled and loaded. While not actively exploited in the wild, the issue causes kernel warnings and improper driver initialization that could degrade WiFi functionality or stability on affected systems.
A Linux kernel scheduler vulnerability in SCHED_DEADLINE task handling causes bandwidth accounting corruption when a deadline task holding a priority-inheritance mutex is changed to a lower priority class via sched_setscheduler(). The vulnerability affects Linux kernel implementations (all versions with SCHED_DEADLINE support) and can be triggered by local unprivileged users running specific workloads like stress-ng, potentially leading to kernel warnings, task accounting underflow, and denial of service. No active exploitation in the wild is currently documented, but the vulnerability is fixed in stable kernel branches as evidenced by the provided commit references.
A race condition in the Linux kernel's i801 I2C driver causes a kernel NULL pointer dereference and panic during boot when multiple udev threads concurrently access the ACPI I/O handler region. The vulnerability affects Linux kernel versions running the i2c_i801 driver on systems with Intel i801 chipsets. An attacker with local access or the ability to trigger concurrent device enumeration during boot can crash the system, resulting in denial of service.
This vulnerability is an AB-BA deadlock in the Linux kernel's PHY (Physical Layer) LED trigger subsystem that occurs when both LEDS_TRIGGER_NETDEV and LED_TRIGGER_PHY are enabled simultaneously. The deadlock arises because PHY LED triggers are registered during the phy_attach phase while holding the RTNL lock, then attempting to acquire the triggers_list_lock, while the netdev LED trigger code does the reverse-holding triggers_list_lock and attempting to acquire RTNL. This deadlock affects all Linux kernel versions with the affected PHY and LED trigger subsystems enabled (cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*), and while not directly exploitable for privilege escalation, it can be triggered to cause a system hang or denial of service by users with network configuration privileges or via userspace LED sysfs writes.
A use-of-uninitialized-variable vulnerability exists in the Linux kernel's radiotap parser that can lead to information disclosure when processing radiotap frames with undefined fields. The vulnerability affects all Linux kernel versions using the radiotap namespace parser (cpe:2.3:a:linux:linux) and occurs when undefined radiotap field 18 is present, causing the iterator->_next_ns_data variable to be compared against an uninitialized value. While no CVSS score or EPSS data is currently available and there is no indication of active exploitation, the vulnerability has been patched across multiple kernel branches as evidenced by six distinct commit fixes.
A NULL pointer dereference vulnerability exists in the Linux kernel's DRM client subsystem within the drm_client_modeset_probe function. When memory allocation for the 'modes' variable fails via kcalloc, the error handling path incorrectly attempts to destroy a NULL pointer, leading to a kernel panic or denial of service. This affects all Linux kernel versions containing this vulnerable code path in the DRM display driver subsystem.
The Linux kernel kalmia USB driver fails to validate that connected USB devices have the required endpoints before binding to them, allowing a malicious or malformed USB device to trigger a kernel crash during endpoint access. This denial-of-service vulnerability affects all Linux kernel versions running the kalmia driver (net/usb/kalmia.c) and requires physical USB device connection or local control of USB device enumeration. While no CVSS score or EPSS probability is formally assigned, the vulnerability has been patched across multiple stable kernel branches, indicating recognition of the issue's severity.
This vulnerability is a resource leak in the Linux kernel's NVMe driver where the admin queue is not properly released during controller reset operations. Systems running affected Linux kernel versions are vulnerable to denial of service through memory exhaustion when NVMe controllers reset repeatedly. While no active exploitation in the wild has been reported and CVSS/EPSS scores are not yet published, the issue affects all Linux distributions and is resolved through kernel patching with fixes available across multiple stable branches.
A stack-out-of-bounds write vulnerability exists in the Linux kernel's BPF devmap implementation where the get_upper_ifindexes() function iterates over upper network devices without properly validating buffer bounds. An attacker with the ability to create multiple virtual network devices (e.g., more than 8 macvlans) and trigger XDP packet processing with BPF_F_BROADCAST and BPF_F_EXCLUDE_INGRESS flags can write beyond allocated stack memory, potentially causing denial of service or arbitrary code execution. The vulnerability affects all Linux kernel versions using the vulnerable devmap code path and has been patched across multiple stable kernel branches, indicating recognition as a real security concern requiring immediate updates.
A use-of-uninitialized-variable vulnerability exists in the Linux kernel's AMD GPU (drm/amdgpu) driver, specifically in the slot reset error handling path. When device recovery fails after a slot reset is called, the code branches to error handling logic that references an uninitialized hive pointer and accesses an uninitialized list, potentially leading to information disclosure or system instability. This affects Linux kernel versions across multiple stable branches, with patches available in the referenced commits.
A deadlock vulnerability exists in the Linux kernel's mcp251x CAN bus driver where the mcp251x_open() function calls free_irq() while holding the mpc_lock mutex during error handling, causing the function to deadlock if an interrupt occurs simultaneously. This affects all Linux kernel versions with the vulnerable mcp251x driver code, and while not actively exploited in the wild (no KEV status indicates no in-the-wild exploitation), it represents a local denial of service condition where a user with appropriate device access can trigger driver initialization failures that hang the system.
A logic error in the Linux kernel's DRBD (Distributed Replicated Block Device) subsystem causes drbd_al_begin_io_nonblock() to fail silently when activity log extent acquisition fails due to spinlock contention, leading to loss of mutual exclusivity guarantees between resync and application I/O operations. This vulnerability affects all Linux kernel versions with the affected DRBD code and can result in kernel crashes via BUG_ON() assertions when activity log references are incorrectly released, as well as potential data consistency issues during active resync operations when concurrent application I/O proceeds without proper exclusivity enforcement.
This vulnerability is a race condition in the Linux kernel's libata subsystem where pending work is not properly canceled after clearing a deferred queue command (deferred_qc), leading to a WARN_ON() condition when the stale work eventually executes. The vulnerability affects all Linux kernel versions with the vulnerable libata code path, impacting systems using ATA/SATA disk controllers. An attacker with local access could trigger this condition through specific command sequences involving NCQ and non-NCQ commands, causing kernel warnings and potential system instability, though direct privilege escalation is not demonstrated.
A null pointer dereference vulnerability exists in the Linux kernel's ice network driver that crashes the system during ethtool offline loopback tests. The vulnerability affects Linux kernel versions running the ice driver (Intel Ethernet Controller driver), and an attacker with local access and CAP_NET_ADMIN privileges can trigger a kernel panic (denial of service) by executing ethtool loopback self-tests. No active exploitation or public POC has been reported; patches are available in stable kernel releases.
A memory management vulnerability in the Linux kernel's EFI boot services implementation causes a leak of approximately 140MB of RAM on systems with CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled, particularly affecting resource-constrained EC2 instances with 512MB total RAM. The vulnerability occurs when efi_free_boot_services() attempts to free EFI boot services memory before the kernel's deferred memory map initialization is complete, resulting in freed pages being skipped and never returned to the memory pool. This is a kernel-level memory exhaustion issue affecting all Linux distributions, though impact is most severe on systems with minimal RAM; no active exploitation or proof-of-concept has been identified as this is a resource leak rather than a code execution vector.