CVE-2026-46680

Workarounds

Ensure that only trusted images are used and that only trusted users have permissions to import images. Alternatively, enforcing a specific numeric runAsUser in the Kubernetes Pod securityContext overrides the USER directive in the image and prevents the bypass. Newer versions of Kubernetes, starting with 1.34, also appear to enforce runAsNonRoot properly regardless of this bug.

Credits

The containerd project would like to thank Lei Wang (@ssst0n3) for responsibly disclosing this issue in accordance with the containerd security policy.

Resources

• https://github.com/advisories/GHSA-265r-hfxg-fhmg (CVE-2024-40635)

For more information

If there are any questions or comments about this advisory:

• Open an issue in containerd
• Send an email to [email protected]

To report a security issue in containerd:

• Report a new vulnerability
• Send an email to [email protected]

A bug was found in containerd where containers launched with a numeric User directive that cannot be parsed as a 32-bit integer are incorrectly treated as a username. If a crafted image provides an /etc/passwd file mapping this large numeric string to root, the container ultimately runs as root (UID 0). This allows the Kubernetes runAsNonRoot restriction to be bypassed, causing unexpected behavior for environments that require containers to run as a non-root user.

An object is accessed using a type that is incompatible with its actual type, causing the runtime to interpret memory incorrectly. Typical impact: memory safety violations, unexpected behavior, or code execution.

Kodem intelligence

This bug has been fixed in the following containerd versions:

• 2.3.1
• 2.2.4
• 2.0.9
• 1.7.32

Note: The containerd 2.1 release has reached its end of life and a fixed version is not provided.

Users should update to these versions to resolve the issue.

1. What is CVE-2026-46680? CVE-2026-46680 is a high-severity type confusion vulnerability in github.com/containerd/containerd (go), affecting versions >= 1.7.27, < 1.7.32. It is fixed in 1.7.32, 2.0.9, 2.2.4, 2.3.1. An object is accessed using a type that is incompatible with its actual type, causing the runtime to interpret memory incorrectly.
2. Which packages are affected by CVE-2026-46680?
   • github.com/containerd/containerd (go) (versions >= 1.7.27, < 1.7.32)
   • github.com/containerd/containerd/v2 (go) (versions >= 2.0.4, < 2.0.9)
3. Is there a fix for CVE-2026-46680? Yes. CVE-2026-46680 is fixed in 1.7.32, 2.0.9, 2.2.4, 2.3.1. Upgrade to this version or later.
4. Is CVE-2026-46680 exploitable, and should I be worried? Whether CVE-2026-46680 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
5. What actually determines whether CVE-2026-46680 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.
6. How do I fix CVE-2026-46680?
   • Upgrade github.com/containerd/containerd to 1.7.32 or later
   • Upgrade github.com/containerd/containerd/v2 to 2.0.9 or later
   • Upgrade github.com/containerd/containerd/v2 to 2.2.4 or later
   • Upgrade github.com/containerd/containerd/v2 to 2.3.1 or later