CVE-2026-43499: Linux kernel · rtmutex: Use waiter::task instead of current in remove_waiter()
Source GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.8 High · fixed in 8.4 : patch affected systems soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 59% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 8.4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 21 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
Description
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 ]
References
- nvd.nist.gov/vuln/detail/CVE-2026-43499 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)
- git.kernel.org/stable/c/3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 (opens in a new tab)
- git.kernel.org/stable/c/3fb7394a837740770f0d6b4b30567e60786a63f2 (opens in a new tab)
- git.kernel.org/stable/c/6d52dfcb2a5db86e346cf51f8fcf2071b8085166 (opens in a new tab)
- git.kernel.org/stable/c/838ce5cb5d93c3ab8b27e75bc6ad905a94b752fd (opens in a new tab)
- git.kernel.org/stable/c/88614876370aac8ad1050ad785a4c095ba17ac11 (opens in a new tab)
- git.kernel.org/stable/c/8a1fc8d698ac5e5916e3082a0f74450d71f9611f (opens in a new tab)
- git.kernel.org/stable/c/d8cce4773c2b23d819baf5abedc62f7b430e8745 (opens in a new tab)
- git.kernel.org/stable/c/f3fa3424bceb128d2be4b3745506b22844b87db7 (opens in a new tab)
- openwall.com/lists/oss-security/2026/07/08/12 (opens in a new tab)