Description

containerd CRI plugin: Incorrect cgroup hierarchy assignment for containers running in usernamespaced Kubernetes pods.

Impact

A bug was found in the containerd's CRI implementation where containerd doesn't put usernamespaced containers under the Kubernetes' cgroup hierarchy, therefore some Kubernetes limits are not honored. This may cause a denial of service of the Kubernetes node.

Patches

This bug has been fixed in containerd 2.0.5+ and 2.1.0+. Users should update to these versions to resolve the issue.

Workarounds

Disable usernamespaced pods in Kubernetes temporarily.

Credits

The containerd project would like to thank Rodrigo Campos Catelin and Piotr Rogowski for responsibly disclosing this issue in accordance with the containerd security policy.

For more information

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Mitigation

Aliases

References