containerd is an open-source container runtime. In versions prior to 1.7.32, 2.0.9, 2.2.4 and 2.3.1, containers launched with a numeric User directive that cannot be parsed as a 32-bit integer are incorrectly treated as a username, leading to runAsNonRoot evasion. If a crafted image provides an /etc/passwd file mapping this large numeric string to root, the container ultimately runs as root (UID 0). This allows the Kubernetes runAsNonRoot restriction to be bypassed, causing unexpected behavior for environments that require containers to run as a non-root user. This issue has been fixed in versions 1.7.32, 2.0.9, 2.2.4 and 2.3.1.