RefluXFS Is Another Root Flaw You Should be Worried About

A regular local user, no special access, quietly rewriting root-owned files on a default RHEL box. That's RefluXFS (CVE-2026-64600), a race condition in the XFS reflink code that turns an ordinary account into root.

The nasty part: the overwrite keeps the file's ownership, permissions, timestamps, and setuid bit intact, survives a reboot, and threw no kernel warning in our testing.

Join us live as we walk through how a stale block mapping becomes root, which Enterprise Linux systems are exposed out of the box, why SELinux and container isolation don't stop it, and how to patch affected kernels without a reboot.