Zero-Day Exploit 'ShieldBreak' Discovered in Microsoft Defender

Security researchers have released details on a zero-day exploit named 'ShieldBreak' that grants SYSTEM-level privileges in Microsoft Defender. This critical vulnerability, discovered after Microsoft's August 2026 Patch Tuesday updates, allows for full system compromise and creates an immediate risk for millions of endpoints, raising concerns about the speed of patch cycles in catching zero-day flaws.