Most Linux LPEs need a race window or a kernel-specific offset. Copy Fail is a straight-line logic flaw — it needs neither. The same 732-byte Python script roots every Linux distribution shipped since 2017. One logic bug in authencesn , chained through AF_ALG and splice() into a 4-byte page-cache write — silently exploitable for nearly a decade. Same script, four distributions, four root shells — ...