CVE-2026-63968
Published: July 22, 2026Last modified: July 22, 2026
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
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Fixed (6.1.177-r0) |
| 25 LTS | linux-lts | Not affected (6.6.89-r0) | |
| Stream | linux-lts | Fixed (6.18.35-r1) |
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
- https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f