containerd's CRI implementation improperly trusts Container Device Interface (CDI) annotations found within untrusted checkpoint image metadata during container restoration. When restoring a container from a checkpoint, containerd preserves CDI-related annotations from the checkpoint archive rather than relying solely on the pod's create-time specification. This allows a user with pod creation permissions to bypass standard Kubernetes resource allocation and device plugin enforcement, injecting arbitrary CDI edits (such as device nodes and host mounts) into the restored container. Successful exploitation requires that the node has CDI enabled and contains a matching host CDI specification for the requested device; environments where CDI is disabled or lacking sensitive device specifications are not affected.
This bug has been fixed in the following containerd versions:
Users should update to these versions to resolve the issue. Recreating existing containers restored from untrusted checkpoints may be necessary to remove smuggled configuration.
Users can mitigate this issue by restricting the restoration of containers from untrusted checkpoint images. If Container Device Interface (CDI) capabilities are not utilized on the node, removing or temporarily relocating host CDI specifications from the default directories (/etc/cdi and /var/run/cdi) will eliminate the reachability of this vulnerability.
The containerd project would like to thank Robert Prast (@robertprast) for responsibly disclosing this issue in accordance with the containerd security policy.
If you have any questions or comments about this advisory:
To report a security issue in containerd:
| Software | From | Fixed in |
|---|---|---|
github.com/containerd/containerd/v2
|
2.1.0 | 2.1.9 |
github.com/containerd/containerd/v2
|
2.2.0 | 2.2.5 |
github.com/containerd/containerd/v2
|
2.3.0 | 2.3.2 |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
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