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vulnerabilities
New Microsoft Defender 'ShieldCrash' zero-day grants SYSTEM access
A researcher under the alias Nightmare Eclipse disclosed a zero-day vulnerability in Microsoft Defender named ShieldCrash that allows attackers to gain SYSTEM-level access. The disclosure followed Microsoft's September 2026 Patch Tuesday update cycle on September 9, 2026.
Why it matters: Organizations running Microsoft Defender are immediately exposed to local privilege escalation attacks; security teams must assess whether workarounds exist and prepare to patch once Microsoft releases a fix.
- Source published
- First seen by Cybersecurity Tracker