On the heels of a record-breaking Patch Tuesday, the disgruntled security researcher known as Nightmare-Eclipse dropped yet another Windows zero-day exploit, which enables privilege escalation and bypasses the fix for a previous Windows exploit released last month.
The latest from the researcher — who also goes by Chaotic Eclipse, MSNightmare, and their X handle, Infinite Nightmare — is the "ShieldCrash" exploit, which they claim is a patch bypass for CVE-2026-69414, or "ShieldBreak." ShieldBreak is a privilege escalation flaw in the Microsoft Malware Protection Engine of Windows Defender.
Nightmare-Eclipse released the ShieldBreak exploit on August's Patch Tuesday, one in a series of exploits for Windows flaws released monthly by the researcher since April. Microsoft has since patched the flaw, but the researcher claims it was not done properly.
"Under specific conditions it is still possible to trigger the exact same problem that was caused by ShieldBreak," they wrote in the "README" file of ShieldCrash's extensive GitHub post. "While Microsoft fixed several things to prevent re-exploiting the issue, they missed a spot where ShieldBreak can still be exploited."