Cybersecurity stocks plunge as Anthropic's 'Claude Mythos' leak sparks AI fear

Investing.com -- Cybersecurity stocks fell Friday, with CrowdStrike (NASDAQ: CRWD) dropping 7%, Palo Alto Networks (NASDAQ: PANW) declining 6%, Zscaler (NASDAQ: ZS) down 4.5%, and Okta (NASDAQ: OKTA), SentinelOne (NYSE: S) and Fortinet (NASDAQ: FTNT) losing 3%.

The declines appeared tied to reports that Anthropic's latest AI model was leaked before launch after descriptions were stored in a publicly-accessible data cache, first reported by Fortune. Details about the new model, codenamed "Claude Mythos," were reportedly stored in a draft blog available in an unsecured and publicly-searchable data store.

The AI startup blamed the leak on "human error" in the configuration of its content management system. The leaked draft introduced a new tier of AI models called "Capybara," which would be larger and more capable than Anthropic's current top-tier Opus model.

According to the leaked document, Capybara achieves higher scores in software coding, academic reasoning, and cybersecurity-related tasks compared to Claude Opus 4.6. The draft described Claude Mythos as "by far the most powerful AI model we've ever developed."

An Anthropic spokesperson told Fortune the company is "developing a general purpose model with meaningful advances in reasoning, coding, and cybersecurity" and is "being deliberate about how we release it."

The draft blog post reportedly warned that the model is "far ahead of any other AI model in cyber capabilities" and could spark a "wave of models that can exploit vulnerabilities in ways that far outpace the efforts of defenders."