ShieldBreak: New Windows Zero-Day Bypasses Microsoft’s RoguePlanet Patch
Researcher Chaotic Eclipse published a PoC bypassing Microsoft's CVE-2026-50656 Defender patch, enabling SYSTEM-level code execution on fully patched Windows systems.
Security researcher Chaotic Eclipse released a proof-of-concept for ShieldBreak, a Microsoft Defender zero-day that fully bypasses the patch for CVE-2026-50656 (RoguePlanet), a race condition in the Malware Protection Engine (mpengine.dll) allowing SYSTEM-level code execution. The PoC was tested on Windows 11 25H2 and Windows Server 2025 with a 100% success rate, and Windows 10 is also vulnerable though not supported by the PoC; the flaw may also leak 8 bytes of memory. Microsoft's MSRC had criticized the researcher's repeated uncoordinated disclosures, including YellowKey (BitLocker bypass), GreenPlasma, and LegacyHive (User Profile Service LPE).
Serial Microsoft 0-day hunter drops yet another Defender exploit
Researcher Nightmare Eclipse released ShieldCrash, a Microsoft Defender zero-day PoC that bypasses September patches and reads files as SYSTEM.
Zero-day researcher Nightmare Eclipse (MSNightmare) published ShieldCrash, their 11th Microsoft zero-day, a proof-of-concept bypass of the ShieldBreak patch (CVE-2026-69414), which itself had bypassed the fix for RoguePlanet (CVE-2026-50656). ShieldCrash works on Windows 10, Windows 11, and Windows Server systems that have applied the September 2026 patches and allows arbitrary file reads as SYSTEM, though not arbitrary writes or a full SYSTEM shell. Microsoft has not said when it plans to patch the issue. The researcher recently also released zero-days affecting CrowdStrike Falcon (FalconFlank), Kaspersky endpoint antivirus (HardBreacher, patched), and Gen Digital's Avast (PrettyPrague).
ShieldBreak Zero-Day PoC Claims Microsoft Defender Patch Bypass With SYSTEM Access
Researcher Chaotic Eclipse released ShieldBreak PoC, a claimed patch bypass for Microsoft Defender flaw CVE-2026-50656, now tracked as CVE-2026-69414.
Researcher Chaotic Eclipse released a PoC for ShieldBreak, a claimed full patch bypass of Microsoft Defender flaw CVE-2026-50656 (RoguePlanet), which can yield SYSTEM privileges. Independent researchers Kevin Beaumont and Will Dormann validated the exploit on Windows 11 25H2 and Windows Server 2025, noting it requires Defender to be enabled. Microsoft assigned CVE-2026-69414 (CVSS 7.8) with an 'Exploitation More Likely' assessment and is investigating, but has not yet released a patch. The article also notes CISA's KEV addition of the actively exploited Windows AFD.sys flaw CVE-2026-68820.
Researcher Drops New Microsoft Defender PoC Showing ShieldBreak Patch Can Be Bypassed
Researcher Chaotic Eclipse released a PoC showing CVE-2026-69414's patch is bypassable, allowing arbitrary file reads as SYSTEM on current Windows.
The researcher known as Chaotic Eclipse published a proof-of-concept for a zero-day in Microsoft Defender, dubbed ShieldCrash, assessed as a patch bypass for ShieldBreak (CVE-2026-69414, CVSS 7.8). The PoC demonstrates an arbitrary file read as SYSTEM with the latest Windows installed, and all supported desktop versions are said to be impacted. Microsoft patched the original issue in Microsoft Malware Protection Engine 1.1.26080.3, which updates automatically. The same researcher recently released PoCs for flaws in CrowdStrike Falcon Sensor, Kaspersky, Avast Antivirus and NVIDIA.