CVE-2026-99070 ipv6: do not warn on route notification size race

Not scored Published 23 Oct 2026 Updated 23 Oct 2026

Exploited in the wild: Not known
Fix: Available

What is CVE-2026-99070?

CVE-2026-99070 is a vulnerability in Linux, published on 23 Oct 2026.

Official description

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

ipv6: do not warn on route notification size race

fib6_info_hw_flags_set() sizes the skb with rt6_nlmsg_size() and later fills it with rt6_fill_node(). With nexthop compatibility mode enabled, a concurrent replacement can grow the group between these independent snapshots. rt6_fill_node() can then legitimately return -EMSGSIZE, so the warning does not prove a sizing bug.

Remove the warning. The existing error path still frees the skb and reports the error to listeners.

Which versions are affected by CVE-2026-99070?

How do I fix CVE-2026-99070?

Upgrade to a fixed version.

Is CVE-2026-99070 being exploited?

There is no known exploitation of CVE-2026-99070 in the wild and no public exploit code.

Sources

Also known as AZL-110960, BELL-CVE-2026-99070, DEBIAN-CVE-2026-99070, GHSA-f9fr-3jhc-3vfj, UBUNTU-CVE-2026-99070.