CVE-2026-63968

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A flaw exists in the IPv6 implementation where an infinite loop can occur within the fib6 select path() function. This happens because writers holding the tb6 lock may execute list del rcu() on first->fib6 siblings without waiting for RCU readers. Consequently, the first->fib6 siblings.next pointer may still point to an old ring, preventing the softirq-side walker from reaching the terminator. The issue is resolved by implementing an inside-loop check using first->fib6 nsiblings as a detach signal.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.