ipv6: use RCU in ip6_output()
CVE-2025-40158 · published 12 Nov 2025
How serious is it
- Severity: high, CVSS score 8.1 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2025-40158?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36 to < 423895685f367b5a0a956bd14b02df0192bded4c, 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36 to < 92803b826e40e49a5e8a6e208f4b4574e9d19426, 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36 to < 0393f85c3241c19ba8550f04a812e7d19f6b3082, 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36 to < 11709573cc4e48dc34c80fc7ab9ce5b159e29695
- Linux Linux: 4.13
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
ipv6: use RCU in ip6_output()
Use RCU in ip6_output() in order to use dst_dev_rcu() to prevent
possible UAF.
We can remove rcu_read_lock()/rcu_read_unlock() pairs
from ip6_finish_output2().
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/423895685f367b5a0a956bd14b02df0192bded4c
- git.kernel.org/stable/c/92803b826e40e49a5e8a6e208f4b4574e9d19426
- git.kernel.org/stable/c/0393f85c3241c19ba8550f04a812e7d19f6b3082
- git.kernel.org/stable/c/11709573cc4e48dc34c80fc7ab9ce5b159e29695
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON