Fifty-four cybersecurity professionals have signed an open letter demanding the White House reverse export controls on two of Anthropic’s most advanced AI models, arguing the restrictions will leave defenders worse off than the attackers they’re trying to stop.
The letter, circulated around June 14, targets a Commerce Department directive issued on June 12 that suspended foreign access to Anthropic’s Fable 5 and Mythos 5 models. Anthropic received the order at 5:21 p.m. ET and, rather than attempt to build nationality-based access filters on the fly, simply disabled the models for everyone globally.
What happened and why it matters
Anthropic launched Fable 5 on June 9 as a safer, more heavily guardrailed successor to Mythos, a model originally developed during the company’s April 2026 Project Glasswing initiative. Mythos had proven remarkably effective at identifying zero-day vulnerabilities, the kind of software flaws that attackers exploit before anyone knows they exist.
Three days after Fable 5’s launch, the Commerce Department dropped its export control hammer. The trigger was reportedly a jailbreak incident that exposed vulnerabilities in the models, raising national security red flags about what might happen if hostile actors gained unrestricted access.
