GPT-5.5 matches heavily hyped Mythos Preview in new cybersecurity tests
By Kyle Orland
Building on yesterday's Social discussion questioning whether comparable models would face similar restrictions, UK's AI Security Institute finds OpenAI's publicly-launched GPT-5.5 matches Anthropic's restricted Mythos Preview model on cybersecurity benchmarks, scoring 71.4% vs 68% on expert-level Capture the Flag challenges. This challenges Anthropic's rationale for restricting Mythos while OpenAI released a comparably capable model publicly.