OpenAI Expands Daybreak With GPT-5.5-Cyber to Help Defenders Patch Security Flaws
Jun 23, 2026
Artificial Intelligence / Codex Security
OpenAI on Monday said it's releasing an improved version of its GPT‑5.5‑Cyber model to trusted defenders as part of the Daybreak initiative the artificial intelligence (AI) company announced last month. Calling GPT‑5.5‑Cyber its "strongest model yet for finding and helping patch software vulnerabilities," OpenAI said the model can "sustain deeper analysis across large codebases" to identify security issues, validate them in a controlled environment, and develop and test patches. In tandem, the tech upstart is releasing an update to the Codex Security plugin to speed up the process of discovering and patching vulnerabilities in existing systems, alongside preventing new vulnerabilities from entering production codebases. "Developers can run deep scans or review recent changes, generate reports with severity, affected code locations, validation evidence, and remediation guidance, trace attack paths, build threat models, validate findings, and genera...
