BigDiskBuster can block Microsoft Defender updates by filling disk space, leaving detection content stale; no patch or advisory exists.

Over the weekend, security researcher Abdelhamid Naceri (also known as Nightmare Eclipse) released another Microsoft Defender zero-day exploit that blocks antivirus updates.

Not quite an EDR-killer, but the proof-of-concept cyber technique creates a silent virus detection gap while service runs normally, no exploit required.

Microsoft has a new Defender anti-virus update for Windows 11 and 10 images. The new update patches several flaws.

BigDiskBuster is a new Microsoft Defender zero-day that can block platform and signature updates across supported Windows versions.

Update May 25, 04:19 EDT: CVE-2026-41091 is a Microsoft Defender local privilege escalation (LPE) flaw known as RedSun, and CVE-2026-45498 is known as UnDefend, a security flaw that can be exploited ...

Microsoft patches two actively exploited zero‑day flaws in Defender, tracked as CVE‑2026‑41091 (privilege escalation) and CVE‑2026‑45498 (denial of service) Updates were shipped automatically via ...