A bug was found in containerd where containers launched through containerd’s CRI implementation with a specially-crafted image configuration could gain access to read-only copies of arbitrary files and directories on the host. This may bypass any policy-based enforcement on container setup (including a Kubernetes Pod Security Policy) and expose potentially sensitive information. Kubernetes and crictl can both be configured to use containerd’s CRI implementation.
This bug has been fixed in containerd 1.6.1, 1.5.10 and 1.4.13. Users should update to these versions to resolve the issue.
Ensure that only trusted images are used.
The containerd project would like to thank Felix Wilhelm of Google Project Zero for responsibly disclosing this issue in accordance with the containerd security policy.
If you have any questions or comments about this advisory: