Image Cache Poisoning via Unvalidated Checkpoint Image References in containerd CRI

CVE-2026-50195 is a critical vulnerability in containerd's CRI checkpoint import process. During import or restore from a checkpoint image, containerd fails to validate the image references embedded in the checkpoint image configuration. An attacker who can create pods can supply a crafted checkpoint image that causes containerd to pull an attacker-controlled image and assign it an arbitrary local tag on the node. This poisons the node-local image cache by making a malicious image appear to be a legitimate cached image reference. On shared Kubernetes nodes, subsequent pods that rely on the poisoned local tag can start the attacker-controlled image instead of the intended one.