Claude Mythos AI Model Uncovers 271 Zero-Day Vulnerabilities in Firefox

Anthropic's Claude Mythos Preview, used in collaboration with Mozilla, identified 271 zero-day vulnerabilities in Firefox (patched in Firefox 150), following an earlier engagement where Claude Opus found 22 vulnerabilities; the report highlights Mythos' high exploitation success rates in testing and its ability to surface long‑buried flaws across critical infrastructure, framing this as a major shift in AI-driven vulnerability research with both defensive benefits and potential offensive implications.