Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-89516
Published: September 12, 2026
Vulnerability identifier: #VU149284
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89516
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a race condition in process_deferred_reenq_users in the sched_ext subsystem when processing deferred reenqueue users for a destroyed dispatch queue. A local user can trigger deferred reenqueue processing after a dispatch queue is destroyed to cause a denial of service.
Affected software
Linux kernel
How to mitigate CVE-2026-89516
Install security update from vendor's repository.