Chaotic Eclipse Released ShieldCrash, A PoC For Microsoft Defender Zero-Day
Brief
The researcher Chaotic Eclipse released ShieldCrash, a PoC exploit for a Microsoft Defender Zero-Day vulnerability.
Security researcher Chaotic Eclipse , also known as INFINITE NIGHTMARE, MSNightmare and Nightmare-Eclipse, released a new zero-day exploit targeting Microsoft Defender. The researcher named the exploit ShieldCrash, it triggers an arbitrary file read as SYSTEM.
The researcher claims that Microsoft has not fully fixed the ShieldBreak vulnerability (CVE-2026-69414). According to the researcher, Microsoft closed several ways to exploit the flaw but missed a specific condition that still allows the same attack.
The researcher published a proof of concept (PoC) that can read arbitrary files with SYSTEM privileges, the highest level of access on Windows. He says all supported Windows versions remain vulnerable, even after the September 2026 security updates.