Microsoft Confirms RoguePlanet Defender Zero-Day, Says Patch is in Development - The Hacker News

Microsoft Confirms RoguePlanet Defender Zero-Day, Says Patch is in Development Ravie LakshmananJun 17, 2026Endpoint Security / Vulnerability Microsoft has formally disclosed that it's working to release a patch to address a Defender zero-day codenamed RoguePlanet. The vulnerability has now been assigned the CVE identifier CVE-2026-50656 (CVSS score: 7.8), with the tech giant describing it as a privilege escalation flaw. "Microsoft is aware of an elevation of privilege in the Microsoft Malware Protection Engine in Microsoft Defender, publicly referred to as 'RoguePlanet,'" the company said. "We are working to provide a high-quality security update that addresses this vulnerability."  The development comes nearly a week after a security researcher named Chaotic Eclipse (aka Nightmare-Eclipse) released RoguePlanet, calling the exploit a case of a race condition that grants attackers a shell with SYSTEM-level privileges. "The exploit is a race condition, so it's a hit or miss," the researcher noted. "I have managed to get a 100% success rate on some machines while it struggled to work on others." In an update shared Tuesday, the researcher added: "I forgot to add one thing, surprisingly, the PoC for RoguePlanet works regardless if real-time protection is on or not, which is hilarious. I think it even works in the case of passive mode, but not really sure, haven't tested that." Microsoft told The Hacker News last week that it's aware of the reported vulnerability and that it's "actively investigating the validity and potential applicability of these claims." RoguePlanet is the fourth Defender vulnerability disclosed by Chaotic Eclipse after BlueHammer (CVE-2026-33825), UnDefend (CVE-2026-45498), and RedSun (CVE-2026-41091), all of which have since been patched by Microsoft. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share SHARE  endpoint security, Microsoft Defender, privilege escalation, Vulnerability, Windows Security, Zero-Day ⚡ Top Stories This Week Microsoft Patches Record 206 Flaws, Including Three Zero-Days and Critical RCE Bugs Palo Alto Warns of Active Exploitation of PAN-OS GlobalProtect VPN Flaw Over 400 Arch Linux AUR Packages Hijacked to Deploy Infostealer and eBPF Rootkit Microsoft Defender RoguePlanet Zero-Day Grants SYSTEM Access on Updated Windows Cybersecurity Stars Awards 2026: Winners Announced Across 95 Categories Researchers Build Self-Replicating AI Worm That Operates Entirely on Local, Open-Weight Models Critical Splunk Enterprise Flaw Lets Attackers Run Code Without Authentication China-Linked Hackers Backdoored Linux Login Software to Hide for Nearly a Decade Anthropic Releases Claude Fable 5, Its Most Powerful AI Yet, With Cyber Safeguards Ivanti, Fortinet, and SAP Release Patches for Multiple Critical Vulnerabilities Chrome V8 Zero-Day CVE-2026-11645 Exploited in the Wild - Patch Now U.S. Orders Anthropic to Suspend Fable 5 and Mythos 5 Access for Foreign Nationals Agentjacking Attack Tricks AI Coding Agents Into Running Malicious Code ⚡ Weekly Recap: Chrome 0-Day, UniFi Exploits, macOS Stealers, VPN Flaw and More New GreatXML Exploit Bypasses Windows BitLocker via Recovery Partition XML Files ThreatsDay Bulletin: Worm Code Leaked, AI Agent Phished, Claude Code Patch + 28 New Stories Load More ▼ ⭐ Featured Resources AI Can’t Stop Every Attack. Learn How Zero Trust Can Block What’s Unknown [Watch Demo] See Which Security Gaps Attackers Could Exploit First Get the 2026 Guide to Govern and Secure Enterprise AI Agents at Scale Have You Outgrown Your MDR? 7 Warning Signs Every CISO Should Check