Microsoft patches RoguePlanet Defender zero-day vulnerability

Microsoft has issued a security update to resolve the zero-day vulnerability known as 'RoguePlanet' (CVE-2026-50656), affecting Microsoft Defender on fully patched versions of Windows 10 and Windows 11. The flaw allows attackers to gain SYSTEM-level privileges through a race condition in the security software, regardless of real-time protection settings. A proof-of-concept exploit was publicly shared by researcher Nightmare Eclipse, who has previously reported several other high-profile vulnerabilities. The issue was resolved with the release of Microsoft Malware Protection Engine version 1.1.26060.3008.