Cybersecurity analysis: GPT-5.5 reaches a similar level of performance as Mythos Preview and is the second model to solve a multi-step cyberattack simulation (AI Security Institute)

AI Security Institute: Cybersecurity analysis: GPT-5.5 reaches a similar level of performance as Mythos Preview and is the second model to solve a multi-step cyberattack simulation — In April, our evaluation of Anthropic's Claude Mythos Preview found that it represented a step up in cyber performance …