{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/workqueue/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":[],"_cs_severities":["high"],"_cs_tags":["linux","kernel","vulnerability","workqueue"],"_cs_type":"advisory","_cs_vendors":[],"content_html":"\u003cp\u003eThe \u0026lsquo;Out-of-Cancel\u0026rsquo; vulnerability class, discovered and detailed in March 2026, highlights a category of security flaws residing within the workqueue cancellation APIs in the Linux kernel. This vulnerability arises when work items are improperly handled during cancellation, potentially leading to use-after-free conditions, race conditions, and other memory corruption issues. The initial report and analysis were published on March 23, 2026. While specific exploits are not detailed in the source material, the nature of kernel vulnerabilities makes them critical for defenders to address. The impact can range from denial of service to privilege escalation and potentially arbitrary code execution within the kernel context. This vulnerability class affects a broad range of Linux systems, making it a widespread concern.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eA user-space program triggers a specific kernel function that queues a work item to a workqueue.\u003c/li\u003e\n\u003cli\u003eThe work item is scheduled for execution, but before it begins, the user-space program requests cancellation of the work item via a workqueue cancellation API.\u003c/li\u003e\n\u003cli\u003eDue to a race condition or improper synchronization, the work item is canceled but not fully removed from the workqueue\u0026rsquo;s internal data structures.\u003c/li\u003e\n\u003cli\u003eThe kernel attempts to access the work item after it has been freed, resulting in a use-after-free vulnerability.\u003c/li\u003e\n\u003cli\u003eAn attacker manipulates memory layout to place controlled data at the memory location of the freed work item.\u003c/li\u003e\n\u003cli\u003eThe kernel code now operates on the attacker-controlled data, leading to memory corruption or information leakage.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the memory corruption to overwrite critical kernel data structures, such as function pointers or security credentials.\u003c/li\u003e\n\u003cli\u003eSuccessful exploitation leads to privilege escalation, allowing the attacker to execute arbitrary code with kernel-level privileges.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eThe \u0026lsquo;Out-of-Cancel\u0026rsquo; vulnerability class can lead to severe consequences, including kernel crashes (denial of service), privilege escalation, and potentially arbitrary code execution within the kernel. A successful exploit could allow an attacker to gain complete control over the affected system. Due to the ubiquitous nature of the Linux kernel, a wide range of systems are potentially vulnerable, impacting servers, desktops, embedded systems, and mobile devices. While the exact number of vulnerable systems is unknown, the widespread use of affected kernel versions implies a significant potential impact.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor kernel logs for errors related to workqueue cancellations to detect potential exploitation attempts. Enable auditd to log kernel function calls related to workqueue management (audit.rules).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Potential Use-After-Free in Workqueue Cancellation\u003c/code\u003e to identify suspicious kernel events related to workqueue operations.\u003c/li\u003e\n\u003cli\u003eInvestigate any reported kernel panics or crashes, focusing on stack traces that involve workqueue-related functions.\u003c/li\u003e\n\u003cli\u003eStay informed about kernel patches and security advisories related to workqueue vulnerabilities and apply them promptly.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-03-25T07:30:12Z","date_published":"2026-03-25T07:30:12Z","id":"/briefs/2026-03-out-of-cancel/","summary":"The 'Out-of-Cancel' vulnerability class stems from flaws in Linux workqueue cancellation APIs, potentially leading to exploitable conditions within the kernel.","title":"Out-of-Cancel Vulnerability Class in Linux Workqueue Cancellation APIs","url":"https://feed.craftedsignal.io/briefs/2026-03-out-of-cancel/"}],"language":"en","title":"CraftedSignal Threat Feed — Workqueue","version":"https://jsonfeed.org/version/1.1"}