US Cyber Agency Using Anthropic's Mythos to Audit Government Code
By Reuters | 06 Jul, 2026

CISA is using Anthropic's AI model Mythos to audit government software even as the company navigates an ongoing standoff with the White House.

Anthropic logo is seen in this illustration taken June 11, 2026. REUTERS/Dado Ruvic/Illustration

The U.S. cyber defense agency CISA is using Anthropic's AI model Mythos to audit government software, three people familiar with the matter said on Monday, another sign of government enthusiasm for adopting the AI startup's tools even as the company navigates an ongoing standoff with the White House.

The Cybersecurity and Infrastructure Security Agency is using Mythos to scan government code repositories for bugs that could leave the door open for foreign spies and cybercriminals, the sources said.

Anthropic did not respond to questions about the initiative. A CISA representative said last month that he would check to see if there was anything to share about the matter but did not respond to further emails.

The scanning is being done by CISA's Attack Surface Evaluation team, according to one of the sources. The team is a group within CISA that conducts digital security assessments and hacking exercises across government.

Two of the sources said the audits had already uncovered a large number of vulnerabilities but did not elaborate. Reuters could not establish exactly how much government code the team had gone through or the nature or severity of the bugs it discovered.

ANTHROPIC'S ROCKY U.S. GOVERNMENT TIES

Anthropic, which has confidentially filed for a U.S. initial ​public offering, has had a tumultuous relationship with the U.S. government. Relations reached a nadir in February after the San Francisco-based company refused ​to remove safeguards ⁠that prevented its AI from being used for autonomous weapons or domestic surveillance. That prompted the Pentagon to slap it with a formal supply-chain risk designation, a label heretofore applied to foreign companies suspected of facilitating espionage.

The extraordinary blacklisting was blocked by a judge in March, and the conflict has eased following the private release of Anthropic's Mythos, an AI model described as extremely capable at finding and exploiting cybersecurity vulnerabilities.

The National Security Agency, the U.S. government's powerful eavesdropping agency, has been using Mythos as far back as April despite the blacklist, Axios has reported. Late last month, the New York Times said that NSA analysts had been testing Mythos in classified settings and coming away impressed with its capabilities. But when Anthropic ⁠rolled ​out a public version of Mythos called Fable, ​which included what it described as cybersecurity safeguards, the White House suddenly demanded that it ban foreigners from running it. This triggered a global shutdown of the model that was lifted only last week.

The NSA and the White House did not immediately respond to requests for comment.

(Reporting by Raphael Satter in Washington; Editing by Matthew Lewis)