OpenAI unveils cybersecurity model with limited rollout days after Anthropic’s model

Published on 16/04/2026 - 12:07 GMT+2

OpenAI has launched a new AI model focused on cyber defence, days after the release of rival Anthropic's Claude Mythos sparked concern about the threat posed by increasingly powerful AI to global cybersecurity.

GPT 5.4 Cyber, a variant of OpenAI's flagship GPT 5.4 model, has fewer restrictions on cybersecurity-related queries when used for legitimate, defensive purposes, the company said.

It also adds capabilities for advanced security work, including binary reverse engineering, which allows researchers to analyse compiled software for malware and vulnerabilities without needing access to its source code.

Because the model is more permissive than standard versions, OpenAI said the rollout will be limited to vetted security vendors, organisations and researchers through its Trusted Access for Cyber programme.

The launch comes one week after Anthropic unveiled Claude Mythos Preview, a model it says can identify thousands of previously unknown, high-severity vulnerabilities across major operating systems and web browsers, capabilities it judged too dangerous for a full public release.

In late March, a data leak revealed that Anthropic was developing a new AI model that its own engineers warned posed "unprecedented cybersecurity risks".

The model, Claude Mythos Preview, has since been released in restricted form as part of Project Glasswing, Anthropic's effort to use the technology to harden critical software before it falls into the wrong hands.

Anthropic said the model is too dangerous for a full public release because of the scale and sophistication of the cyberattacks it could enable.

In tests, the model was able to find previously unknown flaws in the Linux kernel — which underpins most of the world's servers — and chain them together into working exploits capable of giving an attacker full control over affected devices.

Access to Mythos Preview has been restricted to 12 founding partners, including Amazon Web Services, Apple, Microsoft, Google and Cisco, as well as more than 40 other organisations responsible for critical software infrastructure.