← Back to feed
Vulnerabilities & PatchesEmerging1 sourceSep 22, 2026 · 14:04via Security Affairs

Chaotic Eclipse Released BigDiskBuster, A PoC For Windows Defender Update DoS Zero-Day

Brief

The researcher Chaotic Eclipse released BigDiskBuster, a PoC exploit for a Windows Defender Update DoS 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 BigDiskBuster, it triggers a Denial of Service Vulnerability in Windows Defender Update.

The security researcher claims to have developed BigDiskBuster, a proof-of-concept that can block Microsoft Defender from receiving platform and signature updates.

“This proof of concept is similar to UnDefend , it prevents windows defender from performing platform/signature updates.” wrote the expert. “Seems to work on all supported windows versions but PoC is a bit buggy and needs some rewritting but you get the idea.”

Read more on Security Affairs