US Gov Demands Anthropic Block Foreign Access to Fable 5 and Mythos 5

The US Department of Commerce ordered Anthropic to immediately block foreign-national access to its frontier models Fable 5 and Mythos 5 after reporting a jailbreak that can elicit sensitive cybersecurity assistance; Anthropic instead suspended both models globally, arguing the cited vulnerability is narrow and that nationality-based access controls are impractical. The action has provoked criticism from researchers and international partners and is likely to intensify regulatory debate over AI export controls, research disruption, and market fragmentation.