Arbitrary host CRI log file read via symlink following in CRI checkpoint restore

Impact

A bug was found in containerd where the CRI plugin restores container.log from a checkpoint image without validating a symlinked path. This could result in reading an arbitrary file on the host via kubectl logs.

Patches

This bug has been fixed in the following containerd versions:

• 2.3.2
• 2.2.5
• 2.1.9

Users should update to these versions to resolve the issue.

Workarounds

Ensure that only trusted images and checkpoints are used.

Credits

The containerd project would like to thank @gouldnicholas and @davidrxchester, Yuming Zhang and Song Li of Zhejiang University, Sangwon Ryu (@sangwon090), Henry Beberman (@hbeberman) of Microsoft, the GKE Security Team using Gemini, Anthropic Research, in collaboration with Claude, Robert Prast (@robertprast), Kyle Elliott (@kyle-elliott-tob) of Trail of Bits, and Zhenchen Wang (@Plucky923), who independently discovered and responsibly disclosed this issue in accordance with the containerd security policy.

For more information

If you have any questions or comments about this advisory:

• Open an issue in containerd
• Email us at security@containerd.io

To report a security issue in containerd: * Report a new vulnerability * Email us at security@containerd.io