CVE-2025-21768

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux6c8702c60b88651072460f3f4026c7dfe2521d12 < 5ab11a4e219e93b8b31a27f8ec98d42afadd8b7aaffected
LinuxLinux6c8702c60b88651072460f3f4026c7dfe2521d12 < 4c0f200c7d06fedddde82209c099014d63f4a6c0affected
LinuxLinux6c8702c60b88651072460f3f4026c7dfe2521d12 < 92191dd1073088753821b862b791dcc83e558e07affected
LinuxLinux4.10affected
LinuxLinux0 < 4.10unaffected
LinuxLinux6.12.16 <= 6.12.*unaffected
LinuxLinux6.13.4 <= 6.13.*unaffected
LinuxLinux6.14 <= *unaffected

Weaknesses

References