Anthropic Mythos 5 Fails CAPTCHA Challenges in Hacking Eval
September 14, 2026
Mythos 5 failed to resolve CAPTCHAs during hacking evaluations. The model's chain of thought spent significant cycles attempting unsuccessfully to bypass these security measures.
HOW THIS AFFECTS YOU
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researcherThis identifies a specific reasoning failure mode in agentic security testing.
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policyCAPTCHAs remain a viable barrier against current frontier model autonomy.