Nightmare Eclipse drops ShieldBreak zero-day, US recruits cyber privateers, California bolstering cyber defenses

Windows Defender Zero-Day 'ShieldBreak,' California's AI Cyber Defense, and US 'Cyber Privateers' A researcher known as Nightmare Eclipse published a new Windows zero-day called ShieldBreak that exploits Windows Defender to escalate from low-level access to full system control across Windows 10/11 (including 25H2) and Windows Server 2025, claiming it bypasses Microsoft's patch for their earlier…