Black & White Path

Jun 24, 2026 · Information Security

OpenAI’s GPT‑5.5‑Cyber Beats Mythos with 85.6% on CyberGym

OpenAI’s new GPT‑5.5‑Cyber model outperforms Anthropic’s Mythos on multiple security benchmarks, achieving 85.6% on CyberGym and 39.5% on ExploitGym, while the accompanying Daybreak initiative introduces the Codex Security plugin, Patch the Planet programme, and trusted‑access collaborations, prompting a shift in defensive priorities toward rapid patching.