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 ]

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History

Thu, 21 May 2026 13:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416

Thu, 21 May 2026 12:30:00 +0000

Type Values Removed Values Added
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 ]
Title rtmutex: Use waiter::task instead of current in remove_waiter()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-21T12:17:49.281Z

Reserved: 2026-05-01T14:12:56.014Z

Link: CVE-2026-43499

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-21T13:16:19.300

Modified: 2026-05-21T13:16:19.300

Link: CVE-2026-43499

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-21T14:15:13Z

Weaknesses