The U.S. government on Friday ordered Anthropic to immediately suspend access to Claude Fable 5 and Mythos 5, its two most advanced AI models, for all foreign nationals due to national security concerns over a jailbreak vulnerability.
Anthropnic complied but disputed the severity, stating the identified vulnerabilities are 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 would "essentially halt all new model deployments for all frontier model providers." David Sacks, co-chair of the President's Council of Advisers on Science and Technology, said on Saturday that the administration hopes Anthropic will fix the issue, adding "the ball is in Anthropic's court."