OpenAI DayBreak – GPT-5.5-Cyber

OpenAI is expanding its Daybreak cybersecurity initiative, which now incorporates an updated Codex Security plugin and the full GPT-5.5-Cyber model. The project also includes a partner network with over 25 security firms and several governments, shifting its focus from identifying vulnerabilities to automatically patching them. OpenAI states that GPT-5.5-Cyber outperforms Anthropic's Mythos on a cybersecurity benchmark. This initiative and its new model have been noted and discussed within practitioner communities.