CVE-2026-53495: containerd: CRI ExecSync Goroutine Leak Leads to Node-Level Denial of Service

A bug in containerd’s CRI ExecSync implementation allows exec probes and lifecycle hooks with background child processes to keep containerd’s stdio-drain goroutines indefinitely blocked. Because the I/O drain phase lacks a default timeout or context cancellation handling, repeated ExecSync invocations (like probes) that include long-lived background processes against a container can cause containerd to leak goroutines and host memory. Over time, this resource exhaustion can cause the containerd daemon to be terminated by the OOM killer, rendering containerd unavailable until it is restarted. This issue affects containerd on Linux systems running with the CRI plugin enabled. Users not using containerd’s CRI implementation or not running containers on Linux are not affected.