CVE-2026-53493: Containerd has image-pull DoS via crafted OCI index graph amplification

A vulnerability exists in containerd’s image pull handlers where a crafted OCI image index containing deeply nested or heavily fanned-out descriptor graphs can cause unbounded CPU and memory consumption. During the PullImage operation, the recursive traversal and processing of child descriptors lack sufficient depth and breadth limits, and fail to adequately deduplicate identical descriptors. This unbounded traversal leads to excessive resource allocation.

Consequently, pulling a malicious image reference can result in prolonged stalls during container creation and significant resource pressure on the host system. This issue occurs entirely during the image pull phase, prior to any container execution.