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

Microsoft confirmed a zero-day vulnerability in Microsoft Defender, codenamed RoguePlanet, on March 18, 2026. The flaw, now identified as CVE-2026-50656 with a CVSS score of 7.8, allows for privilege escalation within the Microsoft Malware Protection Engine. Microsoft stated it is aware of the elevation of privilege vulnerability and is actively developing a patch to address it. The company has not yet provided a timeline for the patch's release but is prioritizing its development. This disclosure follows reports from security researchers who identified the vulnerability and its potential impact on user systems. The CVE details indicate that successful exploitation could allow an attacker to gain elevated privileges on a compromised system, potentially leading to further malicious activities. Microsoft Defender is a critical component of Windows security, designed to protect against malware and other threats.