containerd is an open-source container runtime. Versions prior to 2.3.2, 2.2.5 and 2.1.9 contain a vulnerability in the CRI checkpoint import process where it fails to validate the image references specified within a checkpoint image's configuration. An attacker with permissions to create pods can use a crafted checkpoint image to force containerd to pull a malicious image and assign it an arbitrary local tag, thereby poisoning the node's local image cache.

Subsequently, if other pods on the same node attempt to use the poisoned tag with an IfNotPresent (or Never) pull policy, they will unknowingly execute the attacker's malicious image instead of the legitimate one. This can lead to a compromise of the affected pods, allowing the attacker to execute arbitrary code under the victim pod's identity. This issue has been fixed in versions 2.3.2, 2.2.5 and 2.1.9.