ShieldBreak, identified as CVE-2026-69414, is a zero-day vulnerability in the Microsoft Malware Protection Engine that allows low-privileged local attackers to escalate privileges to SYSTEM. The public proof of concept was released on August 12, 2026, and Microsoft recognized the CVE on August 14, 2026. No patch is currently available. ShieldBreak exploits an elevation-of-privilege vulnerability by manipulating file processing during the cloud-file hydration process in Microsoft Defender, allowing attackers to control processes with elevated privileges. The exploit is functional on Windows 11 25H2 and Windows Server 2025. Qualys VMDR can detect this vulnerability using a specific query, and organizations can use Qualys TruRisk™ Eliminate for mitigation until a patch is released.