Security Researcher Discloses New Windows Zero-Day Bug Amid Ongoing Feud with Microsoft

A security researcher has published details of a new Windows vulnerability, dubbed ShieldBreak, which allows hackers to gain system-wide access. The release comes despite Microsoft's earlier threat of legal action over similar disclosures.

New Windows Vulnerability Exposes Users to Hackers

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. The new bug, dubbed ShieldBreak, takes advantage of a flaw in Windows Defender, the anti-malware and security engine built into Windows.

According to the researcher's post, ShieldBreak allows the hacker to escalate their permissions from a low-level user to full access to the device and its data. The bug works on Windows 10, Windows 11 (including the latest 25H2 version), and Windows Server 2025, the researcher said.

Security researcher Will Dormann verified that the bug works and that Windows Defender must be enabled for the exploit to work.

The latest exploit builds on an earlier exploit that the researcher developed, dubbed RoguePlanet, which Microsoft rolled out a patch for. However, the researcher implied that Microsoft's fix was not sufficient and that their latest exploit demonstrates a full bypass of the earlier patch.

Microsoft has not yet released a patch for the ShieldBreak bug. The bug is considered a zero-day because the software maker was given no time to patch the bug before it was publicly disclosed.

Microsoft's Ongoing Feud with Security Researchers

This is the latest in a long back-and-forth between the security researcher and the software giant over the company's alleged handling of their bug reports. In a series of blog posts, the security researcher claimed that Microsoft mistreated them and did not handle their bug reports sufficiently.

• The release of this new zero-day is the latest in a series of disclosures by the security researcher, who has previously released details of several bugs affecting Microsoft's products, including Windows.
• Microsoft has faced heavy rebuke from the security community, many of whom described similar experiences with Microsoft's handling of their bug reports.
• The company initially threatened to take legal action against security researchers who release details of zero-days outside of the company's disclosure policies, but later walked back the comments in a social media post.

Microsoft's Response to the Latest Vulnerability

When reached for comment, an unnamed Microsoft spokesperson said the company is "aware of the reported vulnerability and is actively investigating the validity and potential applicability of these claims."

• Microsoft has not yet released a patch for the ShieldBreak bug, and it remains to be seen how the company will respond to the latest disclosure.
• The release of this new zero-day highlights the ongoing tension between security researchers and the software giant over the handling of bug reports.
• As the security community continues to push for greater transparency and cooperation, Microsoft must navigate the complex landscape of bug disclosure and patching.