After Microsoft threatened legal action, a security researcher publishes a new Windows zero-day bug | TechCrunch

After receiving legal threats from Microsoft, security researcher Nightmare Eclipse released a new Windows zero-day vulnerability called ShieldBreak. This vulnerability exploits a flaw in Windows Defender, allowing attackers to elevate permissions from low-level users to full access to the device. It affects Windows 10, Windows 11 (including version 25H2), and Windows Server 2025. The researcher has released Windows applications designed to exploit this vulnerability and confirmed that it is effective only when Defender is enabled. Microsoft has not yet released a patch for ShieldBreak; although the previously released RoguePlanet vulnerability has been patched, Nightmare Eclipse stated that its latest exploit achieved complete bypass. A Microsoft spokesperson said the company is aware of the vulnerability and is investigating it.