BlockBeats News, June 13th, Anthropic released a statement stating that the U.S. government, citing national security authority, has issued an export control directive requiring the suspension of all foreign national access to Fable 5 and Mythos 5, whether located within or outside the U.S., including Anthropic's foreign national employees. The practical impact of this directive is that the company must immediately disable Fable 5 and Mythos 5 for all customers to ensure compliance. Access to other Anthropic models is unaffected. Anthropic received the government directive today at 17:21 ET. The letter did not provide specific details on national security concerns. Anthropic understands that the government believes it has become aware of a method to bypass or "jailbreak" Fable 5. The company has reviewed this specific technique used to identify a small number of previously known, minor vulnerabilities in a demo that appear relatively straightforward, and other publicly available models can also identify these vulnerabilities without the need for bypass.

Anthropic stated that prior to Fable's release, the company conducted thousands of hours of red team testing on Fable security measures with the U.S. government, UK AISI, several private third-party entities, and internal teams. The tests showed that Fable's security measures were significantly stronger than any previously deployed models, and currently, no testers have found a widely applicable jailbreaking method to bypass the model's security measures. The government has only provided the company with a verbal indication of a potential narrow, non-generalizable jailbreak, essentially requiring the model to read a specific codebase and fix software defects. Anthropic has reviewed relevant reports and confirmed that the demonstrated capability can already be widely provided by other models, including OpenAI's GPT-5.5, which is used daily by defenders to secure systems.

Anthropic stated that the company will comply with the government's legal directive to remove all user access to Fable 5 and Mythos 5. However, Anthropic disagrees with using a narrow potential jailbreak discovery as a reason to recall a commercially deployed model serving millions of users. Anthropic mentioned that if this standard applies to the entire industry, it would essentially hinder all leading model providers from deploying new models. The government should have the ability to prevent insecure deployments, but this process should be transparent, fair, clear, and based on technical facts. Anthropic believes that this action did not follow these principles and called it a misunderstanding, stating that the company is working to restore access as soon as possible.