CVE-2026-98538

A flaw was found in the Linux kernel's writeback subsystem. This flaw allows a local user to cause a Denial of Service (DoS) by triggering prolonged processor stalls. When the kernel cleans up offline control group writeback structures with a large number of cached files, it repeatedly rescans already processed entries while holding an internal lock. This inefficient traversal can trigger a soft lockup where processors become stuck, rendering the system unresponsive.

This vulnerability is rated as having a Moderate impact because triggering the denial of service requires an unprivileged local attacker or specific container workloads to manage an unusually large volume of cached file references under active memory cgroups. In standard Red Hat Enterprise Linux environments, CPU lockups occur only when terminating dying cgroups that hold millions of writeback items simultaneously. The issue affects system availability without compromising confidentiality or data integrity.

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.