Cybersecurity Stocks Slide Following Anthropic 'Claude Mythos' Data Leak

Cybersecurity equities faced downward pressure Friday following reports that AI startup Anthropic inadvertently exposed internal data. The lapse allegedly revealed details of an unreleased model, “Claude Mythos,” and an invite-only CEO retreat.

Significant Security Lapse at Anthropic

Anthropic reportedly left nearly 3,000 assets accessible via its content management system (CMS). According to Fortune, cybersecurity researcher Alexandre Pauwels discovered the unsecured data cache. The files included draft blog posts, images, and research papers.

The company secured the data on Thursday after being notified of the issue. Anthropic attributed the incident to “human error in the CMS configuration.” A spokesperson told Fortune the issue was “unrelated to Claude, Cowork, or any Anthropic AI tools.”

Leaked Details of “Claude Mythos”

The exposed documents reportedly contain information on a new AI model. Anthropic described this model in internal drafts as a “step change” in capabilities. The company confirmed it is testing a model with significantly better performance in “reasoning, coding, and cybersecurity.”

The leak also detailed an upcoming retreat for European CEOs. Anthropic CEO Dario Amodei is scheduled to attend the event in the U.K.

AI Tools Rattle Cybersecurity Markets

This is not the first time Anthropic has shaken the sector. In February, the company unveiled Claude Code Security, an AI tool designed to autonomously hunt software vulnerabilities. The announcement sparked a massive sell-off in traditional security vendors.

Investors fear AI-enabled tools from players like Anthropic and OpenAI could undermine demand for legacy security suites. Wedbush Securities analyst Dan Ives previously called the move a “bullish signal,” arguing it validates the importance of the cybersecurity frontier.

Ives stated, “Anthropic with Claude Security going after the cyber security market with a code tool validates our thesis that cyber security is the next frontier for the AI Revolution. Based on all checks Claude will not replace vendors….BUT speaks to oppy on doorstep for PANW, CRWD, ZS.”

Competitive Pressure and “SaaSpocalypse”

The insurance and software sectors have also felt the heat from AI disintermediation. Bank of America Global Research warned that AI could put over $15 billion of insurance commissions at risk. In February, a “SaaSpocalypse” sent giants like Salesforce Inc. (NYSE:CRM) and Workday Inc. (NASDAQ:WDAY) to 52-week lows.

Price Action Performance (Pre-market/Friday):

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