Microsoft Defender Zero-Day 'RoguePlanet' Enables Full System Takeover, No Patch Yet

Executive Briefing

• Exposes critical zero-day flaw CVE-2026-50656 in Microsoft Defender affecting fully patched Windows 10 and 11 devices
• Exploits a race condition allowing attackers to spawn command prompts with full system-level privileges
• Researcher 'Nightmare Eclipse' published a proof-of-concept exploit after alleging Microsoft removed prior repositories from GitHub and GitLab
• Microsoft confirms awareness and is developing a patch, but no release date has been provided
• Same researcher has recently disclosed additional Windows vulnerabilities including BlueHammer, RedSun, MiniPlasma, and YellowKey