CVE-2026-98258

A flaw was found in the Linux kernel's POSIX CPU timer subsystem. A race condition can occur when modifying or deleting a timer concurrently with its expiration handling, allowing the timer to be freed while still queued on an active expiry list. A local user could exploit this use-after-free (UAF) flaw to cause a Denial of Service (DoS) via a system crash or potentially escalate privileges.

Red Hat has evaluated this issue as having a Moderate severity impact because successful exploitation requires an authenticated local user to win a tight race condition during timer operations. The issue affects core kernel timer handling on newer releases such as Red Hat Enterprise Linux 10, while earlier platforms like RHEL 8 and 9 do not include the problematic code. Although the resulting memory corruption can destabilize the system or allow elevated access, the high execution complexity limits overall risk.

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.