OpenAI’s GPT-5.5 Matches Claude Mythos in Cyberattack Capabilities: AI Security Institute

In brief

• GPT-5.5 can autonomously execute sophisticated cyberattacks, completing a 32-step corporate network simulation and cracking a 12-hour security puzzle in just 10 minutes.
• Offensive AI cyber capability is rapidly improving across developers, with AISI warning further advances could arrive…