OpenAI's cybersecurity model just beat the Anthropic Mythos AI model that the U.S. government yanked offline—and it's still up and running.
Anthropic's Mythos 5 sits at 83.8% on the same leaderboard. Claude Opus 4.7, Anthropic's more broadly available model, scored 73.1%.
The government pointed to a jailbreak—a technique for bypassing an AI model's built-in safety limits, similar to finding a master key that unlocks a high-security door. Anthropic had no reliable way to verify user nationality at scale, so it disabled both models for everyone, everywhere.
A few days later, the government grounded Anthropic's aircraft.
A different playbookTwenty-eight security firms—including CrowdStrike, Cisco, and Cloudflare—have joined its Cyber Partner Program to embed GPT-5.5 into their products for vetted customers. Per OpenAI's own blog, Codex Security tool has scanned over 30 million commits across 30,000 codebases and logged more than 500,000 fixed vulnerabilities since launching in March.
The company is also expanding a partner program so security firms can integrate these capabilities into their own tools, and it launched “Patch the Planet,” an initiative to help fix vulnerabilities in widely used open-source projects.
That said, GPT-5.5-Cyber is not for general use. It's available only to verified security professionals, and OpenAI ran pre-deployment tests with federal agencies—including the Center for AI Standards and Innovation and the Office of the National Cyber Director—before launch. That's the same restricted-access approach Anthropic attempted with Mythos, but OpenAI cleared its approach with the government first.
As of June 23, Fable 5 and Mythos 5 remain offline—eleven days into a suspension with no official restoration date from Anthropic or the Commerce Department.
