Developers of major Linux distributions have begun shipping patches to address a local privilege escalation (LPE) vulnerability arising from a logic flaw. The newly disclosed LPE, dubbed Copy Fail (CVE-2026-31431), comes from a vulnerability in the Linux kernel's authencesn cryptographic template. "An unprivileged local user can write four controlled bytes into the page cache of any readable file on a Linux system, and use that to gain root," the writeup from security biz Theori explains. The kernel reads the page cache when it loads a binary, so modifying the cached copy amounts to altering the binary for the purpose of program execution. But doing so doesn't trigger any defenses focused on file system events like inotify . The proof of concept exploit is a 10-line, 732-byte Python script capable of editing a setuid binary to gain root on almost all Linux distributions released since 2017.…