- June 13, 2026
Mythos 5, Fable 5: Why the US Has Suspended Access To Anthropic’s Advanced AI Models
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The US government has ordered artificial intelligence company Anthropic to suspend access to its latest AI models, Fable 5 and Mythos 5, citing national security concerns.
According to Anthropic, the government believes it has become aware of a technique that can bypass some of the safeguards built into Fable 5.
The US government has ordered artificial intelligence company Anthropic to suspend access to its latest AI models, Fable 5 and Mythos 5, citing national security concerns. The move marks one of the most significant interventions by Washington in the deployment of frontier AI systems and could have implications for businesses, governments and developers worldwide, including in India.
What has happened?
Anthropic on Friday said it had received a directive from the US government requiring it to disable access to Fable 5 and Mythos 5 for all foreign nationals, both inside and outside the United States.
“The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance. Access to all other Anthropic models will not be affected,” the company said in a statement.
The directive reportedly applies not only to customers but also to foreign-national employees working at Anthropic.
The suspension comes just days after Anthropic launched Fable 5, a commercially available model that is based on the more powerful Mythos 5 system, access to which had already been tightly restricted due to cybersecurity concerns.
Why has the US government intervened?
According to Anthropic, the government believes it has become aware of a technique that can bypass some of the safeguards built into Fable 5.
The company said it was informed of the concern through a government letter received on June 12. While the communication did not specify the exact national security threat, Anthropic said officials appear to be concerned about a potential “jailbreak” method that could allow users to exploit the model’s advanced capabilities.
The move follows an executive order signed by US President Donald Trump earlier this month creating a framework for the federal government to assess national security risks posed by advanced AI systems before their public release.
The order reflects growing concern in Washington that highly capable AI models could be misused for cyberattacks, intelligence gathering, or other activities that may threaten national security.
What is the alleged vulnerability?
Anthropic defended its models. The company said it reviewed the reported technique and concluded that it is a “narrow, non-universal jailbreak” that essentially involves asking the model to analyse a specific codebase and identify software vulnerabilities.
According to Anthropic, such capabilities are already available in several leading AI systems and are commonly used by cybersecurity professionals to strengthen digital defences.
“We disagree that the finding of a narrow potential jailbreak should be cause for recalling a commercial model deployed to hundreds of millions of people,” the company said. “If this standard was applied across the industry, we believe it would essentially halt all new model deployments for all frontier model providers.”
Why are Mythos and Fable considered sensitive?
Mythos is regarded as one of the most advanced AI systems developed by Anthropic. The model has reportedly demonstrated sophisticated coding, cybersecurity and autonomous problem-solving capabilities.
Anthropic has previously limited access to Mythos because of concerns that its capabilities could be misused by malicious actors.
Fable 5 was introduced as a more widely accessible version of the technology while retaining many of the advanced features that make Mythos attractive to enterprises and developers.
The government appears to be concerned that these capabilities could potentially be adapted for offensive cyber operations if adequate safeguards are bypassed.
What does Anthropic say?
Anthropic has publicly challenged the government’s decision and described it as a “misunderstanding”.
“We believe the government should have the ability to block unsafe deployments, as part of a statutory process that is transparent, fair, clear, and grounded in technical facts,” the company said. “This action does not adhere to those principles.”
The company added that it is working with authorities and hopes to restore access to the affected models as soon as possible.
Anthropic also defended its safety framework, noting that it employs a “defence in depth” approach and retains customer data for 30 days in Fable 5 to help identify and mitigate jailbreak attempts.
What is the impact on India?
The suspension could have significant implications for India, one of Anthropic’s fastest-growing markets.
The company recently partnered with Tata Consultancy Services (TCS) to provide access to its AI models for tens of thousands of employees. Infosys has also announced collaborations involving Anthropic’s AI technology for enterprise applications.
About the Author
Haris is Deputy News Editor (Business) at news18.com. He writes on various issues related to personal finance, markets, economy and companies. Having over a decade of experience in financial journalis…Read More
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