Microsoft has another Windows security nightmare on its hands

Microsoft has confirmed another Windows 10 vulnerability is being actively exploited, with attackers taking advantage of a security loophole that remains unpatched. Visiting a maliciously designed webpage or opening a compromised document could be enough to allow hackers to take control of your PC, Microsoft admits, though it has a number of threat mitigation suggestions to reduce the risk.

The MSHTML Remote Code Execution Vulnerability (CVE-2021-40444) was confirmed on September 7, 2021. “Microsoft is investigating reports of a remote code execution vulnerability in MSHTML that affects Microsoft Windows,” the company said. “Microsoft is aware of targeted attacks that attempt to exploit this vulnerability by using specially-crafted Microsoft Office documents.”

Such a document would need to be opened on a PC in order for the exploit to work, not simply be saved to it. “An attacker could craft a malicious ActiveX control to be used by a Microsoft Office document that hosts the browser rendering engine,” Microsoft explains. “The attacker would then have to convince the user to open the malicious document. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.”