Anthropic Mythos: Coding, Reasoning & Zero-Day Cybersecurity Capabilities

We briefly mentioned the new Anthropic model leak in the previous blog post, we now have more information about it:

• Software engineering and coding — It acts like a senior-level engineer, spotting subtle bugs, self-correcting, and achieving high scores on benchmarks (e.g., ~93.9% on SWE-bench Verified vs. 80.8% for Opus 4.6).
• Complex reasoning — Big jumps on math (e.g., much higher on USAMO 2026), science, and knowledge work.
• Cybersecurity — This is the headline feature. It autonomously discovers and exploits zero-day vulnerabilities at a scale and speed that far exceeds previous models and even most expert humans.

Sources: Project Glasswing, tweet, tweet, tweet