CVE-2026-64119

A flaw was found in the Linux kernel's Layer 2 Tunneling Protocol (L2TP) implementation. An unprivileged local user can exploit a vulnerability in the session unhashing mechanism by concurrently issuing session management commands. This can lead to an infinite loop, causing the host CPU to be indefinitely pinned and resulting in a denial of service (DoS) for the system.

This vulnerability is rated as Moderate severity because exploitation requires local access and is limited to causing a denial of service without exposing or altering sensitive system data. On affected platforms, an unprivileged user in a netns sandbox can initiate competing L2TP session requests, leading to an RCU list traversal loop that hangs the executing CPU core. Older releases like Red Hat Enterprise Linux 8 and 9 do not ship the introduced code and remain unaffected.

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.