A Linux kernel flaw still lets you escape an Ubuntu container, with a public exploit to prove it

Patched upstream on August 6, 2026 in the Linux kernel, CVE-2026-80521 remains unfixed in Ubuntu 26.04, 24.04, and 22.04 LTS, and DepthFirst published a container-escape exploit on September 22. If you host untrusted workloads, apply the upstream patch or isolate them in microVMs.