OpenAI has expanded its Daybreak cybersecurity initiative with a new version of GPT 5.5 Cyber and an updated Codex Security plugin designed to help developers find, validate and patch software vulnerabilities.
The company said artificial intelligence has accelerated the discovery of security flaws, shifting the industry’s main bottleneck from finding vulnerabilities to fixing them before attackers can exploit them.
GPT 5.5 Cyber is OpenAI’s most capable model for advanced authorized cybersecurity work. The model can analyze large codebases, trace potential attack paths, validate vulnerabilities in controlled environments and develop and test patches for human review.
The model scored 85.6% on CyberGym, compared with 81.8% for the standard GPT 5.5 model. CyberGym measures whether an AI agent can reproduce known vulnerabilities in software environments.
GPT 5.5 Cyber also scored 39.5% on ExploitGym, compared with 25.95% for GPT 5.5, and reached 69.8% on SEC Bench Pro, compared with 63.1% for the standard model.
