CVE-2026-46173

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)

PUBLISHED Reserved 2026-05-13 | Published 2026-05-28 | Updated 2026-06-01 | Assigner Linux

Product status

References

git.kernel.org/...c/3d6fb8a7690c23e3213c4b008f64d89a44b98737

git.kernel.org/...c/640b4c00fb0e2920327435f6176cbefc3c546165

git.kernel.org/...c/7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34

git.kernel.org/...c/6f49f94f3b11fe8bff1bf2a054143789e76aaf17

git.kernel.org/...c/9756b3db5db6c2f5eccb32dddbd88eb4c54f575e

git.kernel.org/...c/c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891

cve.org (CVE-2026-46173)

nvd.nist.gov (CVE-2026-46173)

Download JSON