CVE-2025-21768 Information

Description

In the Linux kernel the following vulnerability has been resolved:

net: ipv6: fix dst ref loops in rpl seg6 and ioam6 lwtunnels

Some lwtunnels have a dst cache for post-transformation dst. If the packet destination did not change we may end up recording a reference to the lwtunnel in its own cache and the lwtunnel state will never be freed.

Discovered by the ioam6.sh test kmemleak was recently fixed to catch per-cpu memory leaks. I’m not sure if rpl and seg6 can actually hit this but in principle I don’t see why not.

Reference

https://git.kernel.org/stable/c/4c0f200c7d06fedddde82209c099014d63f4a6c0 https://git.kernel.org/stable/c/5ab11a4e219e93b8b31a27f8ec98d42afadd8b7a https://git.kernel.org/stable/c/92191dd1073088753821b862b791dcc83e558e07