CVE-2022-36109

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. Users should update to this version when it is available. 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.

Thanks to Steven Murdoch for reporting this issue.

Workarounds

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.

References

https://www.benthamsgaze.org/2022/08/22/vulnerability-in-linux-containers-investigation-and-mitigation/

For more information

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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.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2022-36109 has a CVSS score of 5.3 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (20.10.18); upgrading removes the vulnerable code path.

Kodem intelligence

This bug is fixed in Moby (Docker Engine) 20.10.18. Users should update to this version when it is available.

1. What is CVE-2022-36109? CVE-2022-36109 is a medium-severity incorrect authorization vulnerability in github.com/docker/docker (go), affecting versions < 20.10.18. It is fixed in 20.10.18. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2022-36109? CVE-2022-36109 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/docker/docker are affected by CVE-2022-36109? github.com/docker/docker (go) versions < 20.10.18 is affected.
4. Is there a fix for CVE-2022-36109? Yes. CVE-2022-36109 is fixed in 20.10.18. Upgrade to this version or later.
5. Is CVE-2022-36109 exploitable, and should I be worried? Whether CVE-2022-36109 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2022-36109 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2022-36109? Upgrade github.com/docker/docker to 20.10.18 or later.