The Day the US Government Shut Down the Most Powerful AI (www.pentesty.co)

On June 12, 2026, Anthropic faced a government order to shut down its cutting-edge AI models, Claude Fable 5 and Mythos 5, just three days after their launch. The U.S. Department of Commerce mandated the suspension of these models for all users, citing national security concerns after a third party revealed a jailbreak technique that could exploit Mythos 5's advanced offensive cybersecurity capabilities. Mythos 5, designed for defenders to quickly identify vulnerabilities, was restricted to a select group, while Fable 5 was a public version with safety filters. Anthropic's drastic decision to disable both models globally reflects the urgency and sensitivity surrounding AI technologies with offensive potential. The incident represents a significant moment for AI and cybersecurity, illustrating the government's active monitoring of AI capabilities. This regulatory action sets a precedent for how frontier models may be controlled, paralleling the historical Crypto Wars over encryption technologies. With prompt injection techniques now publicly documented, security professionals are urged to reevaluate their AI dependencies and strengthen defenses against emerging threats. As AI technologies evolve rapidly, teams must prepare for potential disruptions caused by regulatory actions while ensuring robust security measures that can withstand manipulation attempts.