Copy.Fail Linux Vulnerability

copy.fail is a high-impact Linux kernel local privilege escalation disclosed with a working PoC that uses AF_ALG sockets and splice() to write four bytes at a time into the page cache of files the attacker does not own, bypassing on-disk integrity checks; it affects major distributions, can break shared-infrastructure isolation (containers, CI, WSL2), and requires kernel updates or custom seccomp profiles to mitigate.