Anthropic says its new model, Mythos Preview, is a big jump in AI cyber capability, so instead of releasing it broadly it is giving controlled early access to defenders through Project Glasswing. The goal is to find and patch vulnerabilities before similar models spread.

• Cyber capability in AI models has been rising for years as a side effect of better coding ability, and Mythos Preview is a notably large step up.
• Anthropic chose not to release Mythos Preview generally, giving selected defenders early access to find and fix vulnerabilities first.
• Project Glasswing brings many major companies together to address the cyber risks posed by increasingly capable AI systems.

A US official told AP that Anthropic’s Mythos model identified vulnerabilities in classified government systems within hours during Project Glasswing tests with intelligence agencies. The Trump administration then barred foreign access to Mythos and its limited Fable 5 model under a security directive, prompting cybersecurity experts to warn that restricting these tools could weaken US defenses.

• Anthropic's Mythos model found vulnerabilities across nearly all tested classified US government systems in hours, not weeks, per NSA/Cyber Command head Gen. Joshua Rudd
• The Trump administration barred foreign nationals from accessing Mythos 5 and Fable 5, and Anthropic responded by disabling the models for all customers, not just foreign users
• Over 100 cybersecurity leaders (including Adobe and Nvidia executives) are pushing to reverse the ban, arguing Mythos isn't uniquely capable—other models do similar security auditing—and restricting it could weaken US defenses against rival states