# OpenAI says new GPT-5.5-Cyber outperforms Anthropic's Mythos on cybersecurity benchmark

> Source: <https://the-decoder.com/openai-says-new-gpt-5-5-cyber-outperforms-anthropics-mythos-on-cybersecurity-benchmark/>
> Published: 2026-06-23 10:43:17+00:00

OpenAI is expanding its Daybreak cybersecurity initiative with an updated Codex Security plugin, the full GPT-5.5-Cyber model, and a partner network with more than 25 security firms and several governments. The focus shifts from finding vulnerabilities to patching them automatically.

The article [OpenAI says new GPT-5.5-Cyber outperforms Anthropic's Mythos on cybersecurity benchmark](https://the-decoder.com/openai-says-new-gpt-5-5-cyber-outperforms-anthropics-mythos-on-cybersecurity-benchmark/) appeared first on [The Decoder](https://the-decoder.com).