High [CVE-2026-46680] Privilege escalation via incorrect user ID handling

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. This vulnerability allows a crafted container image to bypass the Kubernetes `runAsNonRoot` restriction, potentially leading to privilege escalation where the container runs as the root user (UID 0).

This can cause unexpected behavior in environments designed to enforce non-root user execution. Red Hat OpenShift Container Platform and its layered products include the containerd Go library as a build-time dependency for various components.

The vulnerable code path responsible for parsing User directives during container runtime spec generation is not exercised. Therefore, although the containerd library is present in shipped binaries, the vulnerability is not exploitable in the context of Red Hat products.