Accelerating and Modernizing ATOs with OpenAI’s Trusted Access for Cyber
Introduction On February 5, 2026, OpenAI introduced Trusted Access for Cyber (TAC), an identity- and trust-based access framework designed to give verified defenders more useful access to advanced cyber capabilities while preserving safeguards against misuse.[1] TAC launched alongside GPT-5.3-Codex, which OpenAI described as its most cyber-capable frontier reasoning model at the time.[2] Since then, the program has moved quickly. OpenAI introduced Codex Security in research preview on March 6, 2026; expanded TAC on April 14 with additional access tiers and GPT-5.4-Cyber; and, most recently, announced GPT-5.5 with TAC and a limited preview of GPT-5.5-Cyber on May 7, 2026.[3][4][5] This is not just another AI coding assistant or vulnerability scanner. TAC is a framework for controlled access to powerful dual-use cyber capabilities. Codex Security is one of the first major applications built on that foundation: an agentic application security system that uses deep repository context, threat modeling, validation, and patch generation