The 'ShieldBreak' flaw can let an attacker use Windows Defender to escalate their privileges on the OS. Microsoft previously threatened legal action against the researcher, Nightmare Eclipse.

Nightmare Eclipse has released a new Microsoft Defender zero-day exploit named "ShieldBreak" after Microsoft released the August 2026 Patch Tuesday security updates.

For most people using a supported and fully updated Windows 11 computer, yes: Microsoft Defender Antivirus and the other protections inside Windows Security are sufficient as the primary antivirus.

Microsoft says a new Defender capability isolated a compromised device and stopped a ransomware attack in 128 seconds.

Learn how BitLocker, passkeys, Microsoft Defender, and other Windows 11 security features protect your data, accounts, apps, and devices.

Looking for the best antivirus for Windows 11? Check out our top picks to protect your device as well as your system and network to the core!

This voice experience is generated by AI. Learn more. This voice experience is generated by AI. Learn more. Microsoft and CISA confirm Defender zero-days exploited in the wild. Microsoft has started ...

Microsoft Defender automatically isolated a compromised QNET endpoint in 129 seconds, stopping a multi-stage attack before the payload could persist or spread.

Microsoft is named a Leader in the 2026 IDC MarketScape for MDR services. Discover how Microsoft Defender Experts MDR combines AI, threat intelligence, and human expertise.

Microsoft has confirmed that Windows Server updates from last month's Patch Tuesday break some Microsoft 365 Defender features that use the network data reporting service. Redmond describes Microsoft ...

In this post, we will show you how to find the Windows Defender Antivirus signature version in Windows 11. Microsoft Defender is Windows’ built-in antivirus that helps protect your PC from viruses, ...