Microsoft patches RoguePlanet Defender zero-day vulnerability

Microsoft has patched a zero-day vulnerability in Microsoft Defender, tracked as CVE-2026-50656 and dubbed 'RoguePlanet', which could allow attackers to gain SYSTEM privileges via a race condition exploit. The vulnerability affects fully patched Windows 10 and 11 systems, regardless of real-time protection status. It was disclosed by a researcher known as Nightmare Eclipse, who has previously revealed other Windows zero-day exploits. Microsoft addressed the flaw through an update to the Malware Protection Engine and has warned against malicious exploitation of such vulnerabilities.

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