GoKawiilOn 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."
Related:Patch Tuesday Sets Another Record With 974 CVEs
The proof-of-concept (PoC) exploit released on GitHub "demonstrates an arbitrary file read as SYSTEM with September 2026" and affects all supported Windows versions, according to the exploit's GitHub description.
Dark Reading contacted Microsoft for comment on the ShieldBreak exploit and its validity, but the company did not respond at press time.
Ongoing Feud with Microsoft
Nightmare Eclipse appears to show no signs of dropping their vendetta against Microsoft, which started in April with the release of BlueHammer zero-day exploit and stemmed from a disagreement over bug reports to the software giant.
At one point Microsoft appeared to threaten legal action against the researcher, a stance that largely was met with disdain by the security community. Nightmare-Eclipse apparently remains undaunted, and has continued dropping fresh zero-day exploits on Microsoft's monthly Patch Tuesdays, which could give attackers weeks to weaponize the flaws unless the company releases out-of-band patches.
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