Anthropic’s Mythos AI broke into almost all NSA classified systems in hours
Anthropic’s Mythos AI broke into almost all NSA classified systems in hours
Publish Date: 2026-06-22 10:06:00
Source Domain: securityaffairs.com
Anthropic’s Mythos AI broke into almost all NSA classified systems in hours
Pierluigi Paganini
June 22, 2026
Senate testimony claims Anthropic’s Mythos AI breached NSA and Cyber Command systems in hours, prompting a U.S.-ordered shutdown.
On June 12, the Trump administration directed Anthropic to restrict access to Fable 5 and Mythos 5, its two most capable models, exclusively to US citizens. Because verifying every user’s nationality in real time isn’t practically possible, Anthropic’s only option was to shut both models down for everyone. Allies included. No warning.
The U.S. government ordered Anthropic to limit access to its Fable 5 and Mythos 5 AI models to U.S. citizens after a jailbreak was discovered.
That includes Five Eyes partners, Australia, the UK, Canada, and New Zealand, and it blocked the UK AI Security Institute, the main international body for testing frontier AI models, from accessing systems it was actively evaluating.
Then came the Senate testimony. According to a report by The Economist citing a Senate Intelligence Committee hearing, Anthropic’s Mythos model had penetrated nearly all classified systems managed by the NSA and US Cyber Command. Senator Mark Warner stated on June 11 that General Joshua Rudd, who leads both agencies, told him directly that Mythos had done it, and not in weeks.
“Encryption was a potent technology, but narrow in its application. AI is far more powerful and versatile. On June 11th Mark Warner, the vice-chair of the Senate Intelligence Committee, said that General Joshua Rudd, who leads the National Security Agency and the Pentagon’s Cyber Command, had told him that Mythos “broke into almost all of our classified systems, not in weeks, but in hours”.”reported The Economist.
“Advanced AI differs from encryption in another respect, too. Whereas cryptography eventually became widely available abroad, America…
