CVE-2026-63968

Description

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

References

• https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b
• https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae
• https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2
• https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9
• https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3