# CVE-2026-43499

In 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 ]

- Page: https://www.vulneraibility.com/cve/CVE-2026-43499
- CVSS: 7.8
- Known exploited: not in CISA KEV as of our last sync
- EPSS: 5.37% (percentile 92.8)
- Unvetted proof-of-concept code on GitHub: 182 GitHub proofs of concept (first 2026-06-27)
- CISA SSVC: exploitation poc, automatable no, technical impact total (assessed 2026-08-22)
- Weakness: CWE-416
- Published: 2026-05-21

## Affected versions

- Linux: affected >= 8161239a8bcce9ad6b537c04a1fa3b5c68bae693 and < f3fa3424bceb128d2be4b3745506b22844b87db7; >= 8161239a8bcce9ad6b537c04a1fa3b5c68bae693 and < 838ce5cb5d93c3ab8b27e75bc6ad905a94b752fd; >= 8161239a8bcce9ad6b537c04a1fa3b5c68bae693 and < d8cce4773c2b23d819baf5abedc62f7b430e8745; >= 8161239a8bcce9ad6b537c04a1fa3b5c68bae693 and < 8a1fc8d698ac5e5916e3082a0f74450d71f9611f; >= 8161239a8bcce9ad6b537c04a1fa3b5c68bae693 and < 6d52dfcb2a5db86e346cf51f8fcf2071b8085166; >= 8161239a8bcce9ad6b537c04a1fa3b5c68bae693 and < 3fb7394a837740770f0d6b4b30567e60786a63f2; >= 8161239a8bcce9ad6b537c04a1fa3b5c68bae693 and < 88614876370aac8ad1050ad785a4c095ba17ac11; >= 8161239a8bcce9ad6b537c04a1fa3b5c68bae693 and < 3bfdc63936dd4773109b7b8c280c0f3b5ae7d349; 2.6.39; fixed in < 2.6.39, >= 5.10.261 and <= 5.10.*, >= 5.15.212 and <= 5.15.*, >= 6.1.175 and <= 6.1.*, >= 6.6.140 and <= 6.6.*, >= 6.12.86 and <= 6.12.*, >= 6.18.27 and <= 6.18.*, >= 7.0.4 and <= 7.0.*, >= 7.1 and <= *

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://git.kernel.org/stable/c/f3fa3424bceb128d2be4b3745506b22844b87db7
- [other] https://git.kernel.org/stable/c/838ce5cb5d93c3ab8b27e75bc6ad905a94b752fd
- [other] https://git.kernel.org/stable/c/d8cce4773c2b23d819baf5abedc62f7b430e8745
- [other] https://git.kernel.org/stable/c/8a1fc8d698ac5e5916e3082a0f74450d71f9611f
- [other] https://git.kernel.org/stable/c/6d52dfcb2a5db86e346cf51f8fcf2071b8085166
- [other] https://git.kernel.org/stable/c/3fb7394a837740770f0d6b4b30567e60786a63f2
- [other] https://git.kernel.org/stable/c/88614876370aac8ad1050ad785a4c095ba17ac11
- [other] https://git.kernel.org/stable/c/3bfdc63936dd4773109b7b8c280c0f3b5ae7d349
- [other] http://www.openwall.com/lists/oss-security/2026/07/08/12
- [other] https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- [other] https://cert-portal.siemens.com/productcert/html/ssa-457936.html
- [other] https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.