OpenAI Launches GPT-5.4-Cyber to Boost Defensive Cybersecurity

OpenAI unveils GPT-5.4-Cyber, a cybersecurity-focused model built to help defenders analyze malware and fix software bugs. The company is also expanding its Trusted Access for Cyber (TAC) program to thousands of verified experts.

OpenAI has released GPT-5.4-Cyber, a new version of its flagship AI. This launch comes just one week after Anthropic’s new AI model Mythos (Claude Mythos) rollout. The new model is a variant of the main GPT-5.4 system, specifically optimized for defensive cybersecurity use cases.

According to OpenAI’s announcement, the goal is to provide better tools for network and system defenders “responsible for keeping systems, data, and users safe,” so that they can “find and fix problems faster.”

Scaling the Defense Program

Along with the new model, OpenAI is expanding its Trusted Access for Cyber (TAC) program, which first launched in February 2026. This project is now available to thousands of authenticated individual ...