Cybersecurity experts protest US ban on Anthropic's powerful AI models
Original: Cybersecurity vets protest ‘dangerous’ US government ban on Anthropic’s most powerful models
Why This Matters
Highlights policy tension between AI security measures and legitimate cybersecurity defense capabilities in national security regulation.
Seventy-six cybersecurity veterans, including former Facebook security chief Alex Stamos, signed an open letter opposing the U.S. government's export control order on Anthropic's Fable and Mythos models, arguing the restriction removes defensive cybersecurity tools.
On June 15, 2026, a group of 76 cybersecurity experts published an open letter to the U.S. government requesting the lifting of export control restrictions on Anthropic's Fable and Mythos AI models. The U.S. government issued the ban on Friday citing national security concerns without public explanation. In response, Anthropic suspended worldwide access to both models. The signatories include prominent industry figures: Alex Stamos (former Facebook chief security officer), Casey Ellis (Bugcrowd founder), Jon Callas (cryptographer and former Apple security manager), Paul Vixie (computer scientist), Dino Dai Zovi (former Block applied security engineering head), Katie Moussouris (Luta Security founder), and Rachel Tobac (SocialProof Security CEO). The letter states the ban removes the best available models from cybersecurity defenders who use them to identify vulnerabilities and improve software security. Mythos launched as a restricted preview in April with approximately 50 companies having initial access, expanded to 150 organizations across 15 countries. Fable, released last week as a public version, included strict guardrails blocking cybersecurity, biology, and chemistry applications. According to Moussouris, the ban may have been triggered by an unpublished Amazon research paper demonstrating a method to bypass Fable's safeguards and access Mythos-level capabilities.