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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-46173

exit: prevent preemption of oopsing TASK_DEAD task

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Status
Published
Published
Updated
Assigning organization
Linux

Description

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)

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 7f80a2fd7db9a55894fd841915236aca611291b5 to < 3d6fb8a7690c23e3213c4b008f64d89a44b98737affected
  • 7f80a2fd7db9a55894fd841915236aca611291b5 to < 640b4c00fb0e2920327435f6176cbefc3c546165affected
  • 7f80a2fd7db9a55894fd841915236aca611291b5 to < 7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34affected
  • 7f80a2fd7db9a55894fd841915236aca611291b5 to < 6f49f94f3b11fe8bff1bf2a054143789e76aaf17affected
  • 7f80a2fd7db9a55894fd841915236aca611291b5 to < 9756b3db5db6c2f5eccb32dddbd88eb4c54f575eaffected
  • 7f80a2fd7db9a55894fd841915236aca611291b5 to < c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891affected

Linux Linux

Default version status: affected

  • 5.17affected
  • 0 to < 5.17unaffected
  • 6.1.175 to ≤ 6.1.*unaffected
  • 6.6.140 to ≤ 6.6.*unaffected
  • 6.12.88 to ≤ 6.12.*unaffected
  • 6.18.30 to ≤ 6.18.*unaffected
  • 7.0.7 to ≤ 7.0.*unaffected
  • 7.1 to ≤ *unaffected

References