CVE-2026-43499: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.8% chance of exploitation in the next 30 days.

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 ]

Affected products

• Linux Linux Kernel: from 2.6.39, before 6.1.175 (fixed in 6.1.175); from 6.2, before 6.6.140 (fixed in 6.6.140); from 6.7, before 6.12.86 (fixed in 6.12.86); from 6.13, before 6.18.27 (fixed in 6.18.27); from 6.19, before 7.0.4 (fixed in 7.0.4)

Published 2026-05-21. Last modified 2026-09-08.