What’s Vulnerable › Vulnerabilities

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

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-23 · updated 2026-10-23

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.

Affected products

• Linux kernel: 5.12 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/291fe0bafee78c95f9f2e7f579f17793fd5a1e5a
• https://git.kernel.org/stable/c/4ac7d92a4698e34e614c254359665b9de1f65283
• https://git.kernel.org/stable/c/7b112bd43f1172fb152e848570a957467008a5ae
• https://git.kernel.org/stable/c/8a3b935b6b6037eefb36bd27a60793a008358e8d
• https://git.kernel.org/stable/c/c97426ec649d99596d8969e1a052c16b14b7b485

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