Researcher Drops BigDiskBuster Zero-Day PoC That Blocks Microsoft Defender Updates
PoC publicMicrosoft DefenderOur summary
A public proof of concept named BigDiskBuster can prevent Microsoft Defender from downloading platform and signature updates by exhausting free space on the C:\ drive. The tool has no assigned CVE and no Microsoft patch or advisory; it may leave Defender running with outdated detection content, although its claimed behavior has not been independently verified. It differs from the previously patched UnDefend issue, CVE-2026-45498, which Microsoft addressed in Antimalware Platform version 4.18.26040.7.
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