U.S. Government Orders Anthropic to Suspend Claude Fable 5, Mythos 5 Models Over Jailbreak Vulnerability

The U.S. government issued an emergency directive on Friday ordering Anthropic to immediately suspend access to its two most advanced AI models, Claude Fable 5 and Mythos 5, citing national security concerns over a potential jailbreak vulnerability. The ban applies to all foreign nationals, including Anthropic employees, and forced the company to disable both models for its entire customer base.

Anthropric complied with the directive but disputed the severity of the finding, stating that the identified vulnerability is relatively simple and already replicable using other publicly available models like OpenAI's GPT-5.5. The company warned that applying this standard industry-wide could halt all frontier AI model deployments.