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

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

By Zack Whittaker
Publication Date: 2026-08-12 15:18:00

A security researcher has published details of a new vulnerability in the latest versions of Windows that allows hackers to gain system-wide access to the user’s device and data, despite facing a legal threat from Microsoft weeks earlier over the release of previously unknown software flaws.

The new bug, dubbed ShieldBreak, is the latest disclosure by security researcher Nightmare Eclipse, who in recent months has published details of several bugs affecting Microsoft’s products, including Windows.

According to Nightmare Eclipse’s post, ShieldBreak takes advantage of a flaw in Windows Defender, the anti-malware and security engine built into Windows. A successful attack allows the hacker to escalate their permissions from a low-level user to full access to the device and its data. 

Nightmare Eclipse published the proof-of-concept exploit as a Windows app, requiring the user to run the app to exploit the bug. The bug works on Windows 10, Windows 11 (including the…