PT-2026-61285 · Linux · Linux

CVE-2026-63968 · Published 2026-07-19 · Updated 2026-07-19

Mitre

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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

Fix

Related Identifiers

CVE-2026-63968

Affected Products

Linux

References · 7

• https://nvd.nist.gov/vuln/detail/CVE-2026-63968 · Security Note
• https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9 · Note
• https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2 · Note
• https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b · Note
• https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3 · Note
• https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae · Note
• https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f · Note