CVE-2026-63968

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ipv6: fix possible infinite loop in fib6_select_path()<br /> <br /> Found while auditing the same pattern Sashiko reported in<br /> rt6_fill_node() [1]. Apply the same fix as<br /> commit f8d8ce1b515a ("ipv6: fix possible infinite loop in fib6_info_uses_dev()").<br /> <br /> Writers holding tb6_lock can list_del_rcu(&amp;first-&gt;fib6_siblings)<br /> without waiting for RCU readers; first-&gt;fib6_siblings.next then<br /> still points into the old ring and this softirq-side walker never<br /> reaches &amp;first-&gt;fib6_siblings as its terminator. fib6_purge_rt()<br /> always WRITE_ONCE()s first-&gt;fib6_nsiblings to 0 before<br /> list_del_rcu(), so an inside-loop check is a reliable detach signal.<br /> <br /> [1] https://sashiko.dev/#/patchset/20260526020227.4857-1-jiayuan.chen%40linux.dev