Anthropic's new Mythos Preview surfaced a 27-year-old vulnerability in OpenBSD — the most-audited operating system in commercial software — and generated 181 working Firefox exploits in a benchmark where Claude Opus 4.6 managed two. Eleven organizations are inside the launch cohort. The rest of us aren't, and the next Mythos won't be gated. What Mythos is, in hard numbers On April 7, Anthropic announced Claude Mythos Preview , a frontier general-purpose model with a step-change in computer security capability. The numbers are the story: A 27-year-old vulnerability in OpenBSD , surfaced by Mythos in the TCP SACK implementation. OpenBSD's audit posture is the high bar in the industry. A 16-year-old vulnerability in FFmpeg's H.264 codec — the media component shipped in nearly every modern browser and video pipeline. A 17-year-old remote code execution vulnerability in FreeBSD's NFS implementation (CVE-2026-4747).…