"Copy Fail" is a rare Linux bug that can turn an unprivileged user into a root admin in seconds

Researchers disclosed Copy Fail, a Linux kernel vulnerability that can let an unprivileged user gain root access.

The flaw, tracked as CVE-2026-31431, enables controlled writes to the page cache and can be weaponized with a small PoC.

Public proof-of-concept code and emergency fixes have already prompted patches across major Linux distributions.

The issue is especially risky for hosting and cloud environments, where one compromise could affect many tenants.