CVE-2026-43499: rtmutex: Use waiter::task instead of current in remove_waiter()
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-08 00:03 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
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 ]
Description quoted from the CVE record (assigned by Linux, published 2026-05-21).
Weakness: CWE-416 Use After Free
How it can be exploited
Exploitable with local access with low attack complexity needing low privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: no. Technical impact: total.
Public exploit evidence (Exploit Observer)
Exploit Observer found 90 code repositories naming this CVE.
Code repositories that name a CVE are often scanners, copies or fakes, and some are malware. Read the code before running anything.
See all 101 references on Exploit Observer
Live scores
- EPSS
- 0.054
some chance of attack soon - VEDAS
- 0.939
strong exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Linux | from 8161239a8bcc before f3fa3424bceb (git commit) from 8161239a8bcc before 838ce5cb5d93 (git commit) from 8161239a8bcc before d8cce4773c2b (git commit) from 8161239a8bcc before 8a1fc8d698ac (git commit) from 8161239a8bcc before 6d52dfcb2a5d (git commit) from 8161239a8bcc before 3fb7394a8377 (git commit) from 8161239a8bcc before 88614876370a (git commit) from 8161239a8bcc before 3bfdc63936dd (git commit) | Not stated |
| Linux | version 2.6.39 | 0 is not affected (up to 2.6.39); 5.10.261 is not affected; 5.15.212 is not affected; 6.1.175 is not affected |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Other references
- https://git.kernel.org/stable/c/f3fa3424bceb128d2be4b3745506b22844b87db7
- https://git.kernel.org/stable/c/838ce5cb5d93c3ab8b27e75bc6ad905a94b752fd
- https://git.kernel.org/stable/c/d8cce4773c2b23d819baf5abedc62f7b430e8745
- https://git.kernel.org/stable/c/8a1fc8d698ac5e5916e3082a0f74450d71f9611f
- https://git.kernel.org/stable/c/6d52dfcb2a5db86e346cf51f8fcf2071b8085166
- https://git.kernel.org/stable/c/3fb7394a837740770f0d6b4b30567e60786a63f2
- https://git.kernel.org/stable/c/88614876370aac8ad1050ad785a4c095ba17ac11
- https://git.kernel.org/stable/c/3bfdc63936dd4773109b7b8c280c0f3b5ae7d349
- http://www.openwall.com/lists/oss-security/2026/07/08/12
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
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