U.S. Orders Anthropic to Suspend Claude Fable 5 and Mythos 5 Access for Foreign Nationals Over National Security Concerns

The U.S. government has ordered Anthropic to suspend access to its most advanced AI models, Claude Fable 5 and Mythos 5, for all users after issuing an export control directive citing national security concerns. Anthropic received the order on June 13, 2026, at 5:21 p.m. ET, instructing it to block access by foreign nationals both inside and outside the U.S. The company stated it believes there was a misunderstanding and is working to restore access as soon as possible. Access to other models remains unaffected.

Anthropic explained that the government believes it has identified a method to bypass, or ‘jailbreak,’ Fable 5. The company reviewed a demonstration of the technique, which it described as identifying a small number of previously known, minor vulnerabilities that are also discoverable by other publicly available models without requiring a bypass. Anthropic emphasized that it has implemented strong guardrails, including safety classifiers to detect misuse and jailbreak attempts, and that no universal jailbreak methods have been developed against its latest models.

The directive comes shortly after the launch of Claude Fable 5 and Mythos 5, the latter described as having the strongest cybersecurity capabilities of any model in the world and accessible only to vetted cyber defenders and critical infrastructure operators. Anthropic’s Red Team previously revealed that Mythos-class models can turn newly disclosed software vulnerabilities into working exploits in hours or minutes, converting N-days into N-hours. The company argued that the discovery of a narrow potential jailbreak should not be the reason for recalling a widely deployed commercial model and called for a transparent, fair, and technically grounded statutory process.

Reports from The Information, Reuters, and The Wall Street Journal indicate that the directive was partly driven by research from Amazon and concerns raised by CEO Andy Jassy with the White House. Amazon reportedly used prompts to get Fable 5 to provide information that could aid cyberattacks. David Sacks, co-chair of the U.S. President’s Council of Advisors on Science and Technology, stated that Anthropic refused to fix a jailbreak identified by a trusted partner. Semafor reported that the decision was motivated by fears that the model had been accessed by a group linked to China.