Anthropic Launches Claude Mythos 5.2, Scoring 76.3% on Cybersecurity Benchmark to Identify 0-Day Flaws

What happened?

Anthropic has launched Claude Mythos 5.2, its latest AI model for cybersecurity engineering, reporting a 76.3% score on CyScenarioBench. Released on November 9 alongside Claude Fable 5.2, the model is designed to help security teams find, reproduce, and fix software vulnerabilities. Access remains controlled because those same skills could also help attackers. The result improves on Mythos 5.1’s 61.7%, a gain of 14.6 percentage points. However, Anthropic notes that each laboratory’s CyScenarioBench scores use different tasks.

Key details

• Anthropic released Claude Mythos 5.2 on November 9 alongside Fable 5.2 for cybersecurity engineering tasks.
• Mythos 5.2 achieved 89.6% on internal CVE Rediscovery evaluation across 1,829 published vulnerabilities.
• Rediscovering known CVEs is not equivalent to detecting unknown zero-day flaws.
• Fable 5.2 and Mythos 5.2 share the same model but have different safeguards for cybersecurity and biology work.
• Cyber Verification Program offers Defense, Red Team, and Specialized Access tiers with varying approval requirements.

Summarised by SecOraLens from Cyber Security News. Always read the original source before acting. How SecOraLens verifies advisories.