CVE-2026-63829

A flaw was found in the Linux kernel's IP Generic Routing Encapsulation (ip_gre) component. This vulnerability allows a local attacker with network administration capabilities in one network namespace to modify a tunnel residing in a different network namespace where they lack privileges. This is due to an insufficient capability check in the changelink() function, which only verifies permissions in the device's network namespace and not the tunnel's. Successful exploitation could lead to unauthorized alteration of network tunnel configurations, potentially causing network disruption or redirection of traffic.

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.