Copy Fail. Как четыре байта дают root в Linux

Researchers at Theori have disclosed a proof-of-concept for CVE-2026-31431, a critical flaw in the Linux kernel's cryptographic subsystem that allows local privilege escalation to root. The bug, rated 7.8 CVSS, affects all popular distributions released since 2017 that lack the specific security update. The exploit leverages an in-place optimization within the AF_ALG interface, where splicing ciphertext from the page cache causes the authencesn template to incorrectly overwrite pages before rejecting decryption requests. Attackers can modify as few as four bytes in the cached binary of privileged programs like /bin/su to bypass authentication checks without altering the on-disk file, effectively granting instant superuser access.