CVE-2026-53239

A flaw was found in the Linux kernel. A race condition exists in the xfrm policy handling, specifically within the xfrm_policy_bysel_ctx() function. This flaw allows for a use-after-free vulnerability, where memory is accessed after it has been released. This can lead to system instability or a denial of service (DoS), making the system unresponsive or causing it to crash.

This vulnerability is rated as Moderate impact for Red Hat Enterprise Linux because triggering the race condition requires local access and specialized administrative privileges to manage IPsec policies. Although a successful exploit could result in a denial-of-service kernel crash or potential privilege escalation via memory corruption, the attack complexity is high due to the strict timing needed to win the race during policy table flushes. Standard system deployments do not grant unprivileged accounts access to modify transform policies unless delegated network administration capabilities or unprivileged user namespaces are present.

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.