CVE-2026-63968

Summary

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

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxd0ec61c9f3583b76aebdbb271f5c0d3fcccd48b2 < 3948a7d92f7678e89e1776bb2d169afcad63b1aeaffected
LinuxLinux52da02521ede55fb86546c3fffd9377b3261b91f < c87cd3cb309634bc8f50a54e2079424f219ac21faffected
LinuxLinux34a949e7a0869dfa31a40416d2a56973fae1807b < 0f7b73c3452635de83b8711b31abdda8e49aad7baffected
LinuxLinuxd9ccb18f83ea2bb654289b6ecf014fd267cc988b < ab9a10969a907b472a0196d999c08ff7144172e3affected
LinuxLinuxd9ccb18f83ea2bb654289b6ecf014fd267cc988b < 9b9d5bd6e3d4c9cecab5407604b690684b2532d2affected
LinuxLinuxd9ccb18f83ea2bb654289b6ecf014fd267cc988b < 9c7da87c2dc860bb17ca1ece942495d28b1ce3b9affected
LinuxLinux11edcd026012ac18acee0f1514db3ed1b160fc6faffected
LinuxLinux6.1.128 < 6.1.176affected
LinuxLinux6.6.75 < 6.6.143affected
LinuxLinux6.12.2 < 6.12.93affected
LinuxLinux6.11.11 < 6.12affected
LinuxLinux6.13affected
LinuxLinux0 < 6.13unaffected
LinuxLinux6.1.176 <= 6.1.*unaffected
LinuxLinux6.6.143 <= 6.6.*unaffected
LinuxLinux6.12.93 <= 6.12.*unaffected
LinuxLinux6.18.35 <= 6.18.*unaffected
LinuxLinux7.0.12 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References