A bug was found in the containerd's CRI implementation where containerd doesn't put usernamespaced containers under the Kubernetes' cgroup hierarchy, therefore some Kubernetes limits are not honored. This may cause a denial of service of the Kubernetes node.
A time-of-check to time-of-use (TOCTOU) vulnerability was found in containerd v2.1.0. While unpacking an image during an image pull, specially crafted container images could arbitrarily modify the host file system.
A bug was found in containerd where containers launched with a User set as a UID:GID larger than the maximum 32-bit signed integer can cause an overflow condition where the container ultimately runs as root (UID 0). This could cause unexpected behavior for environments that require containers to run as a non-root user.