Microsoft today released an emergency software patch to plug a critical security hole in its Internet Explorer (IE) Web browser that attackers are already using to break into Windows computers.

The software giant said it learned about the weakness (CVE-2018-8653) after receiving a report from Google about a new vulnerability being used in targeted attacks.

Satnam Narang, senior research engineer at Tenable, said the vulnerability affects the following installations of IE: Internet Explorer 11 from Windows 7 to Windows 10 as well as Windows Server 2012, 2016 and 2019; IE 9 on Windows Server 2008; and IE 10 on Windows Server 2012.

“As the flaw is being actively exploited in the wild, users are urged to update their systems as soon as possible to reduce the risk of compromise,” Narang said.

According to a somewhat sparse advisory about the patch, malware or attackers could use the flaw to break into Windows computers simply by getting a user to visit a hacked or booby-trapped Web site. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

Microsoft says users who have Windows Update enabled and have applied the latest security updates are protected automatically. Windows 10 users can manually check for updates this way; instructions on how to do this for earlier versions of Windows are here.