Copy Fail (CVE-2026-31431): Deterministic Linux LPE
🔒 On April 29, 2026 researchers disclosed CVE-2026-31431, dubbed Copy Fail, a deterministic local privilege escalation impacting Linux kernels 4.14–6.19.12. The flaw resides in the AF_ALG crypto interface's algif_aead module and permits a controlled four-byte overwrite into the kernel page cache. A standalone 732-byte Python proof-of-concept reliably escalates to root across major distributions. Apply vendor kernel updates immediately or temporarily disable algif_aead; Cortex XDR and XSIAM provide layered detection and mitigation.
