ShieldBreak Zero-Day PoC Claims Microsoft Defender Patch Bypass With SYSTEM Access

Security researcher Chaotic Eclipse has published a proof-of-concept exploit named ShieldBreak that serves as a complete patch bypass for the previously addressed Microsoft Defender vulnerability CVE-2026-50656. The flaw allows attackers to achieve privilege escalation to SYSTEM level on Windows 11 25H2 and Windows Server 2025, rendering recent security updates ineffective. While CISA is simultaneously adding the actively exploited WinSock zero-day CVE-2026-68820 to its Known Exploited Vulnerabilities catalog, this new disclosure highlights lingering issues in the Defender malware protection engine.