Summary
Supplementary groups are not set up properly in github.com/containerd/containerd
Workarounds
Ensure that the "USER $USERNAME" Dockerfile instruction is not used. Instead, set the container entrypoint to a value similar to ENTRYPOINT ["su", "-", "user"] to allow su to properly set up supplementary groups.
References
- https://www.benthamsgaze.org/2022/08/22/vulnerability-in-linux-containers-investigation-and-mitigation/
- Docker/Moby: CVE-2022-36109, fixed in Docker 20.10.18
- CRI-O: CVE-2022-2995, fixed in CRI-O 1.25.0
- Podman: CVE-2022-2989, fixed in Podman 3.0.1 and 4.2.0
- Buildah: CVE-2022-2990, fixed in Buildah 1.27.1
Note that CVE IDs apply to a particular implementation, even if an issue is common.
For more information
If you have any questions or comments about this advisory:
- Open an issue in containerd
- Email us at [email protected]
To report a security issue in containerd:
- Report a new vulnerability
- Email us at [email protected]
Impact
A bug was found in containerd where supplementary groups are not set up properly inside a container. 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.
Downstream applications that use the containerd client library may be affected as well.
The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access. Typical impact: privilege escalation beyond the intended level.
CVE-2023-25173 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 (1.6.18, 1.5.18); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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This bug has been fixed in containerd v1.6.18 and v.1.5.18. Users should update to these versions and recreate containers to resolve this issue. Users who rely on a downstream application that uses containerd's client library should check that application for a separate advisory and instructions.
Frequently Asked Questions
- What is CVE-2023-25173? CVE-2023-25173 is a medium-severity improper privilege management vulnerability in github.com/containerd/containerd (go), affecting versions >= 1.6.0, < 1.6.18. It is fixed in 1.6.18, 1.5.18. The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access.
- How severe is CVE-2023-25173? CVE-2023-25173 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.
- Which versions of github.com/containerd/containerd are affected by CVE-2023-25173? github.com/containerd/containerd (go) versions >= 1.6.0, < 1.6.18 is affected.
- Is there a fix for CVE-2023-25173? Yes. CVE-2023-25173 is fixed in 1.6.18, 1.5.18. Upgrade to this version or later.
- Is CVE-2023-25173 exploitable, and should I be worried? Whether CVE-2023-25173 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
- What actually determines whether CVE-2023-25173 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.
- How do I fix CVE-2023-25173?
- Upgrade
github.com/containerd/containerdto 1.6.18 or later - Upgrade
github.com/containerd/containerdto 1.5.18 or later
- Upgrade