When the Scanner Starts Thinking: Learnings from Mythos & GPT 5.5 Cyber in Security Testing

This Zscaler blog analyzes how advanced AI models (Mythos, GPT 5.5 Cyber) change security testing by enabling multi-step attack-path reasoning, faster discovery of high-impact findings, and more actionable remediation; it describes a three-harness testing methodology (black-box, artifact/code, gray/white-box), summarizes capabilities and key learnings, and provides defensive recommendations (Zero Trust, exposure management, deception, AI red-teaming).