GHSA-CQC6-9F34-295V
Vulnerability from github – Published: 2026-05-21 15:34 – Updated: 2026-09-08 09:35In the Linux kernel, the following vulnerability has been resolved:
rtmutex: Use waiter::task instead of current in remove_waiter()
remove_waiter() is used by the slowlock paths, but it is also used for proxy-lock rollback in rt_mutex_start_proxy_lock() when invoked from futex_requeue().
In the latter case waiter::task is not current, but remove_waiter() operates on current for the dequeue operation. That results in several problems:
1) the rbtree dequeue happens without waiter::task::pi_lock being held
2) the waiter task's pi_blocked_on state is not cleared, which leaves a dangling pointer primed for UAF around.
3) rt_mutex_adjust_prio_chain() operates on the wrong top priority waiter task
Use waiter::task instead of current in all related operations in remove_waiter() to cure those problems.
[ tglx: Fixup rt_mutex_adjust_prio_chain(), add a comment and amend the changelog ]
{
"affected": [],
"aliases": [
"CVE-2026-43499"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-21T13:16:19Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nrtmutex: Use waiter::task instead of current in remove_waiter()\n\nremove_waiter() is used by the slowlock paths, but it is also used for\nproxy-lock rollback in rt_mutex_start_proxy_lock() when invoked from\nfutex_requeue().\n\nIn the latter case waiter::task is not current, but remove_waiter()\noperates on current for the dequeue operation. That results in several\nproblems:\n\n 1) the rbtree dequeue happens without waiter::task::pi_lock being held\n\n 2) the waiter task\u0027s pi_blocked_on state is not cleared, which leaves a\n dangling pointer primed for UAF around.\n\n 3) rt_mutex_adjust_prio_chain() operates on the wrong top priority waiter\n task\n\nUse waiter::task instead of current in all related operations in\nremove_waiter() to cure those problems.\n\n[ tglx: Fixup rt_mutex_adjust_prio_chain(), add a comment and amend the\n \tchangelog ]",
"id": "GHSA-cqc6-9f34-295v",
"modified": "2026-09-08T09:35:29Z",
"published": "2026-05-21T15:34:08Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43499"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3bfdc63936dd4773109b7b8c280c0f3b5ae7d349"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3fb7394a837740770f0d6b4b30567e60786a63f2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6d52dfcb2a5db86e346cf51f8fcf2071b8085166"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/838ce5cb5d93c3ab8b27e75bc6ad905a94b752fd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/88614876370aac8ad1050ad785a4c095ba17ac11"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8a1fc8d698ac5e5916e3082a0f74450d71f9611f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d8cce4773c2b23d819baf5abedc62f7b430e8745"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f3fa3424bceb128d2be4b3745506b22844b87db7"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2026/07/08/12"
}
],
"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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