Description

Moby is an open-source project created by Docker to enable software containerization. A bug was found in Moby (Docker Engine) where supplementary groups are not set up properly. If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases, potentially gaining access to sensitive information or gaining the ability to execute code in that container. This bug is fixed in Moby (Docker Engine) 20.10.18. Running containers should be stopped and restarted for the permissions to be fixed. For users unable to upgrade, this problem can be worked around by not using the `"USER $USERNAME"` Dockerfile instruction. Instead by calling `ENTRYPOINT ["su", "-", "user"]` the supplementary groups will be set up properly.

Severity MEDIUM

CVSS Score 5.3

CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

CWE CWE-863

Public Exploit ✅ No

Source NVD

Published 2022-09-09

Updated 2026-06-15

Modified 2025-01-17

Fix URL https://github.com/moby/moby/commit/de7af816e76a7fd3fbf06bffa6832959289fba32

Software	From version	Fixed in
fedora	—	—
github.com/docker/docker	—	—
moby	—	20.10.18