FKIE_CVE-2026-46173

Vulnerability from fkie_nvd - Published: 2026-05-28 10:16 - Updated: 2026-05-28 13:44
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: exit: prevent preemption of oopsing TASK_DEAD task When an already-exiting task oopses, make_task_dead() currently calls do_task_dead() with preemption enabled. That is forbidden: do_task_dead() calls __schedule(), which has a comment saying "WARNING: must be called with preemption disabled!". If an oopsing task is preempted in do_task_dead(), between becoming TASK_DEAD and entering the scheduler explicitly, bad things happen: finish_task_switch() assumes that once the scheduler has switched away from a TASK_DEAD task, the task can never run again and its stack is no longer needed; but that assumption apparently doesn't hold if the dead task was preempted (the SM_PREEMPT case). This means that the scheduler ends up repeatedly dropping references on the dead task's stack, which can lead to use-after-free or double-free of the entire task stack; in other words, two tasks can end up running on the same stack, resulting in various kinds of memory corruption. (This does not just affect "recursively oopsing" tasks; it is enough to oops once during task exit, for example in a file_operations::release handler)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/640b4c00fb0e2920327435f6176cbefc3c546165
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6f49f94f3b11fe8bff1bf2a054143789e76aaf17
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9756b3db5db6c2f5eccb32dddbd88eb4c54f575e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891
Impacted products
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{
  "cveTags": [],
  "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\u0027t 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\u0027s 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)"
    }
  ],
  "id": "CVE-2026-46173",
  "lastModified": "2026-05-28T13:44:01.663",
  "metrics": {},
  "published": "2026-05-28T10:16:32.923",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/640b4c00fb0e2920327435f6176cbefc3c546165"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6f49f94f3b11fe8bff1bf2a054143789e76aaf17"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9756b3db5db6c2f5eccb32dddbd88eb4c54f575e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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