GHSA-MPR4-2MM3-RWM6
Vulnerability from github – Published: 2026-05-28 12:30 – Updated: 2026-09-08 09:35In 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": [],
"aliases": [
"CVE-2026-46173"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-28T10:16:32Z",
"severity": "HIGH"
},
"details": "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": "GHSA-mpr4-2mm3-rwm6",
"modified": "2026-09-08T09:35:30Z",
"published": "2026-05-28T12:30:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46173"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3d6fb8a7690c23e3213c4b008f64d89a44b98737"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/640b4c00fb0e2920327435f6176cbefc3c546165"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6f49f94f3b11fe8bff1bf2a054143789e76aaf17"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9756b3db5db6c2f5eccb32dddbd88eb4c54f575e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891"
},
{
"type": "WEB",
"url": "https://project-zero.issues.chromium.org/issues/510793286"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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