via TechCrunch AI
Cybersecurity Veterans Protest 'Dangerous' US Government Ban on Anthropic's Most Powerful AI Models
A coalition of dozens of cybersecurity experts, including several well-known industry veterans, has published an open letter urging the U.S. government to lift the export control order on Anthropic's Fable and Mythos AI models.
The letter argues that the ban has deprived cybersecurity defenders of the most effective tools available for identifying vulnerabilities and securing software and products. “To pull the best capabilities away from defenders without a good reason when our adversaries are rapidly advancing is dangerous,” the letter states.
On June 12, 2026, the U.S. government ordered Anthropic to limit the export of Fable and Mythos, citing national security concerns but offering no specific justification, according to Anthropic. In response, the company suspended global access to both models. The open letter, signed by 76 cybersecurity experts as of this writing, includes notable figures such as Alex Stamos, former Facebook chief of security; Casey Ellis, founder of bug bounty platform Bugcrowd; Jon Callas, renowned cryptographer and former Apple security design and architecture manager; computer scientist Paul Vixie; Dino Dai Zovi, former head of applied security engineering at Block; Katie Moussouris, founder of Luta Security; and Rachel Tobac, CEO of SocialProof Security.
When Mythos launched as a preview in April 2026, Anthropic described it as exceptionally powerful at discovering security vulnerabilities and initially restricted access to about 50 companies to prevent malicious use. By June 2026, access had expanded to roughly 150 organizations across 15 countries. The following week, Anthropic released Fable, a publicly accessible version of Mythos with strict guardrails designed to block applications in biology, chemistry, and cybersecurity, as well as to prevent model distillation by competitors. However, cybersecurity experts soon reported that Fable's guardrails were so restrictive that they effectively blocked nearly all cybersecurity-related prompts.
Anthropic has suggested that the White House export control order may have been triggered by a report indicating a jailbreak method could bypass Fable's safeguards to unlock its full Mythos capabilities.