OpenAI’s GPT-5.5 Cyber AI Beats Anthropic’s Banned Mythos Mannequin—And No one’s Shutting It Down

OpenAI’s cybersecurity mannequin simply beat the Anthropic Mythos AI mannequin that the U.S. authorities yanked offline—and it is nonetheless up and operating.

On June 22, OpenAI introduced the full launch of GPT-5.5-Cyber as a part of its Dawn cyber protection program. On CyberGym—a benchmark developed at UC Berkeley that presents AI brokers with 1,507 identified software program vulnerabilities from 188 open-source initiatives and scores them on what number of they will reproduce in a managed setting—the up to date mannequin reached 85.6%.

Anthropic’s Mythos 5 sits at 83.8% on the identical leaderboard. Claude Opus 4.7, Anthropic’s extra broadly accessible mannequin, scored 73.1%.

A less-than-two-point hole on any benchmark would usually be unremarkable. The context right here will not be. Anthropic’s Mythos 5 and Fable 5 have been pulled offline on June 12 after the Donald Trump administration issued an emergency export management directive citing nationwide safety.

The federal government pointed to a jailbreak—a method for bypassing an AI mannequin’s built-in security limits, just like discovering a grasp key that unlocks a high-security door. Anthropic had no dependable option to confirm person nationality at scale, so it disabled each fashions for everybody, in all places.

A few of the harm was self-inflicted. Anthropic spent months describing Mythos as one of the succesful—and most harmful—AI fashions ever constructed, warning in its personal launch documentation that its cybersecurity talents might trigger critical hurt with out the suitable restrictions. Anthropic CEO Dario Amodei revealed an essay on June 10 evaluating frontier AI fashions to plane that security regulators ought to be capable of floor in the event that they fail audits.

A number of days later, the federal government grounded Anthropic’s plane.

It wasn’t the one alarm that week. Anthropic had already come under fire over a hidden filter in Fable 5 that silently degraded the mannequin’s outputs for customers it suspected of constructing competing AI—with out telling them—and was pressured to apologize and reverse the coverage.

A special playbook

Whereas Anthropic negotiates with the Commerce Division and continues its lawsuit in opposition to the Trump administration, OpenAI is extending its attain. Dawn has signed cybersecurity partnerships with Australia, Canada, France, Germany, Japan, South Korea, and EU establishments including the European Union Company for Cybersecurity.

Twenty-eight safety companies—together with CrowdStrike, Cisco, and Cloudflare—have joined its Cyber Associate Program to embed GPT-5.5 into their merchandise for vetted prospects. Per OpenAI’s personal weblog, Codex Safety instrument has scanned over 30 million commits throughout 30,000 codebases and logged greater than 500,000 fastened vulnerabilities since launching in March.

The corporate can be increasing a accomplice program so safety companies can combine these capabilities into their very own instruments, and it launched “Patch the Planet,” an initiative to assist repair vulnerabilities in extensively used open-source initiatives.

That mentioned, GPT-5.5-Cyber will not be for common use. It is accessible solely to verified safety professionals, and OpenAI ran pre-deployment assessments with federal businesses—together with the Middle for AI Requirements and Innovation and the Workplace of the Nationwide Cyber Director—earlier than launch. That is the identical restricted-access strategy Anthropic tried with Mythos, however OpenAI cleared its strategy with the federal government first.

As of June 23, Fable 5 and Mythos 5 stay offline—eleven days right into a suspension with no official restoration date from Anthropic or the Commerce Division.