{"id":"CVE-2026-46173","state":"PUBLISHED","title":"exit: prevent preemption of oopsing TASK_DEAD task","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nexit: prevent preemption of oopsing TASK_DEAD task\n\nWhen an already-exiting task oopses, make_task_dead() currently calls\ndo_task_dead() with preemption enabled.  That is forbidden:\ndo_task_dead() calls __schedule(), which has a comment saying \"WARNING:\nmust be called with preemption disabled!\".\n\nIf an oopsing task is preempted in do_task_dead(), between becoming\nTASK_DEAD and entering the scheduler explicitly, bad things happen:\nfinish_task_switch() assumes that once the scheduler has switched away\nfrom a TASK_DEAD task, the task can never run again and its stack is no\nlonger needed; but that assumption apparently doesn't hold if the dead\ntask was preempted (the SM_PREEMPT case).\n\nThis means that the scheduler ends up repeatedly dropping references on\nthe dead task's stack, which can lead to use-after-free or double-free\nof the entire task stack; in other words, two tasks can end up running\non the same stack, resulting in various kinds of memory corruption.\n\n(This does not just affect \"recursively oopsing\" tasks; it is enough to\noops once during task exit, for example in a file_operations::release\nhandler)","publishedAt":"2026-05-28T09:36:27.892Z","updatedAt":"2026-10-19T19:36:53.446Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"3d6fb8a7690c23e3213c4b008f64d89a44b98737","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"640b4c00fb0e2920327435f6176cbefc3c546165","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"6f49f94f3b11fe8bff1bf2a054143789e76aaf17","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"9756b3db5db6c2f5eccb32dddbd88eb4c54f575e","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/exit.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.17","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.17","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.140","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.88","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.30","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.7","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/exit.c"]}],"references":["https://git.kernel.org/stable/c/3d6fb8a7690c23e3213c4b008f64d89a44b98737","https://git.kernel.org/stable/c/640b4c00fb0e2920327435f6176cbefc3c546165","https://git.kernel.org/stable/c/7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34","https://git.kernel.org/stable/c/6f49f94f3b11fe8bff1bf2a054143789e76aaf17","https://git.kernel.org/stable/c/9756b3db5db6c2f5eccb32dddbd88eb4c54f575e","https://git.kernel.org/stable/c/c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891","https://project-zero.issues.chromium.org/issues/510793286","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/46xxx/CVE-2026-46173.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46173","state":"PUBLISHED","datePublished":"2026-05-28T09:36:27.892Z","dateUpdated":"2026-10-19T19:36:53.446Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.103Z"},"containers":{"cna":{"title":"exit: prevent preemption of oopsing TASK_DEAD task","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nexit: prevent preemption of oopsing TASK_DEAD task\n\nWhen an already-exiting task oopses, make_task_dead() currently calls\ndo_task_dead() with preemption enabled.  That is forbidden:\ndo_task_dead() calls __schedule(), which has a comment saying \"WARNING:\nmust be called with preemption disabled!\".\n\nIf an oopsing task is preempted in do_task_dead(), between becoming\nTASK_DEAD and entering the scheduler explicitly, bad things happen:\nfinish_task_switch() assumes that once the scheduler has switched away\nfrom a TASK_DEAD task, the task can never run again and its stack is no\nlonger needed; but that assumption apparently doesn't hold if the dead\ntask was preempted (the SM_PREEMPT case).\n\nThis means that the scheduler ends up repeatedly dropping references on\nthe dead task's stack, which can lead to use-after-free or double-free\nof the entire task stack; in other words, two tasks can end up running\non the same stack, resulting in various kinds of memory corruption.\n\n(This does not just affect \"recursively oopsing\" tasks; it is enough to\noops once during task exit, for example in a file_operations::release\nhandler)"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"3d6fb8a7690c23e3213c4b008f64d89a44b98737","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"640b4c00fb0e2920327435f6176cbefc3c546165","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"6f49f94f3b11fe8bff1bf2a054143789e76aaf17","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"9756b3db5db6c2f5eccb32dddbd88eb4c54f575e","versionType":"git"},{"version":"7f80a2fd7db9a55894fd841915236aca611291b5","status":"affected","lessThan":"c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/exit.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.17","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.17","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.140","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.88","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.30","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.7","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/exit.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/3d6fb8a7690c23e3213c4b008f64d89a44b98737"},{"url":"https://git.kernel.org/stable/c/640b4c00fb0e2920327435f6176cbefc3c546165"},{"url":"https://git.kernel.org/stable/c/7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34"},{"url":"https://git.kernel.org/stable/c/6f49f94f3b11fe8bff1bf2a054143789e76aaf17"},{"url":"https://git.kernel.org/stable/c/9756b3db5db6c2f5eccb32dddbd88eb4c54f575e"},{"url":"https://git.kernel.org/stable/c/c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891"},{"url":"https://project-zero.issues.chromium.org/issues/510793286"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerability is in the kernel task-exit/scheduler path (`make_task_dead` → `do_task_dead`) of a local process; it is triggered by a task oopsing during its own exit, with no remote network reachability.\nAC:L - Exploitation depends on a preemption-timing window between `set_special_state(TASK_DEAD)` and `__schedule()`, but the attacker can repeatedly spawn exiting+faulting tasks and generate CPU load to induce preemption, making the race winnable; per the uncertainty rule the higher-severity value is chosen.\nPR:L - Any unprivileged local user can spawn processes that exit and fault on the exit path; no real-root or init-namespace privilege is required.\nUI:N - The attacker triggers their own process exit and fault; no action by another user is needed.\nS:U - The use-after-free/double-free corrupts kernel task-stack memory within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The double-free/UAF of the task stack lets two tasks run on the same stack, giving the attacker control over freed memory contents and thus an arbitrary kernel-memory read primitive.\nI:H - 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