CVE-2026-53361 AF_Unix GC vs. MSG_PEEK use-after-free container escape
Summary
CVE-2026-53361 identifies an unprivileged, container-escapable use-after-free in the AF_UNIX socket garbage collector when engaged with MSG_PEEK. A concurrent MSG_PEEK can take a reference that the GC does not properly count, allowing the collector to free a socket still in use and leaving a dangling sk_buff; the race hinges on the gc_in_progress flag potentially reading false mid-run. The write-up documents prior related fixes, lists affected and patched kernel versions, and reports on tested environments across Debian, Ubuntu, CentOS, and RHEL, highlighting patch status and mitigations for container security.