A zero-day is not frightening because it is sophisticated. It is frightening because it is unknown. There is no patch in the moment it matters most. That single condition undermines the comfort most security programs rely on: time. In the past, attackers didn’t need zero-days because they relied on predictable failures in patching and credential hygiene. The sheer labor required to find new vulnerabilities acted as a natural throttler on advanced attacks. Agentic AI removes that friction. By automating the trial-and-error cycle, AI transforms vulnerability research into a high-speed, 24/7 operation, making the once-rare zero-day a scalable threat. What a zero day is and why it matters A zero...