CVE-2026-53166

kernel: futex/requeue: Prevent NULL pointer dereference in remove_waiter() on self-deadlock

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Severity

Moderate

Red Hat Product Security

5.5

CVSS 3.1

Review impact separately from score.

Published · June 25, 2026

Updated · September 30, 2026

Description

A flaw was found in the Linux kernel's futex (Fast Userspace Mutex) requeue mechanism. When a non-top waiter attempts to requeue a Priority Inheritance (PI) futex it already owns, a NULL pointer dereference can occur. This issue, specifically within the remove_waiter() function during a self-deadlock scenario, leads to a kernel crash, resulting in a Denial of Service (DoS).

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

See the security bulletin for a detailed mitigation procedure.

CVSS / CWE

CVSS 3.1 · 5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE-476 · NULL Pointer Dereference