CVE-2026-63994

A flaw was found in the Linux kernel's tunnels module. This vulnerability, categorized as a Use-After-Free (UAF), arises from improper handling of network header pointers during certain packet processing operations. Specifically, functions responsible for building Internet Control Message Protocol (ICMP) packets for Path MTU Discovery (PMTUD) cache header information before memory reallocations, which can lead to the use of freed memory. A local attacker could potentially leverage this to cause a system crash, resulting in a denial of service.

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.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.