In the Linux kernel, the following vulnerability has been resolved:

ipv6: prevent infinite loop in rt6_nlmsg_size()

While testing prior patch, I was able to trigger
an infinite loop in rt6_nlmsg_size() in the following place:

list_for_each_entry_rcu(sibling, &f6i->fib6_siblings,
fib6_siblings) {
rt6_nh_nlmsg_size(sibling->fib6_nh, &nexthop_len);
}

This is because fib6_del_route() and fib6_add_rt2node()
uses list_del_rcu(), which can confuse rcu readers,
because they might no longer see the head of the list.

Restart the loop if f6i->fib6_nsiblings is zero.

References

• https://nvd.nist.gov/vuln/detail/CVE-2025-38588
• https://git.kernel.org/stable/c/3c13db3e47e170bab19e574404e7b6be45ea873d
• https://git.kernel.org/stable/c/46aeb66e9e54ed0d56c18615e1c3dbd502b327ab
• https://git.kernel.org/stable/c/54e6fe9dd3b0e7c481c2228782c9494d653546da
• https://git.kernel.org/stable/c/6d345136c9b875f065d226908a29c25cdf9343f8
• https://git.kernel.org/stable/c/cd8d8bbd9ced4cc5d06d858f67d4aa87745e8f38
• https://git.kernel.org/stable/c/e1b7932af47f92432be8303d2439d1bf77b0be23
• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html