VulnerabilityBleeping Computer
7.0 — HIGH
New Microsoft Defender 'ShieldBreak' zero-day grants SYSTEM privileges
Nightmare Eclipse has released a new Microsoft Defender zero-day exploit named "ShieldBreak" after Microsoft released the August 2026 Patch Tuesday security updates. [...]
🤖 AI BriefingAuto-generated threat analysis
🔍Threat Overview
A new Microsoft Defender zero-day exploit, ShieldBreak, has been discovered by Nightmare Eclipse, allowing attackers to bypass the RoguePlanet vulnerability and gain SYSTEM privileges on fully patched Windows systems. This exploit is part of an ongoing dispute between Microsoft and Nightmare Eclipse over vulnerability disclosure practices.
⚙️Technical Details
Affected Systems
Windows 10Windows 11Windows ServerAttack Vector: LOCAL
💥Impact Assessment
Severity: High
Who Is at Risk
Users of Windows 10, Windows 11, and Windows Server systems with Microsoft Defender enabled
🛡️Recommended Actions
1Enable Microsoft Defender to prevent exploitation
2Keep all software up-to-date with the latest security patches
3Monitor system logs for suspicious activity
📦Affected Products
Microsoft Malware Protection Engine
🔐NVD Verified DataVERIFIED
CVE-2026-50656 ↗CVSS 7 — HIGH
Attack Vector
LOCAL
Complexity
HIGH
Vector String
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HWeaknesses
CWE-59
Affected Products (CPE)
Microsoft Malware Protection Engine
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