Microsoft fixes a bug in Windows Defender that had affected Firefox performance for 5 years

11 Apr. (Portaltic/EP) –

Microsoft has distributed a fix for a bug in Windows Defender that affected the performance of computers when using Mozilla’s Firefox browser, and has been known for five years.

five years ago the mozilla forums registered complaints from users who had detected that Microsoft’s ‘antimalware’ service, Windows Defender, was doing a excessive consumption of the computer’s CPU (greater than 30%) when using Firefox at the same time.

The bug present in Windows Defender has been fixed this monthwith the March 2023 monthly update, which Microsoft began distributing April 4, and that has arrived this Tuesday to the operating system. In addition to Windows 10 and 11, it will also come to Windows 7 and 8.1 versions.

Specifically, the Windows Defender MsMpEng.exe executable component performed too many communications with VirtualProtecta memory protection feature of the Windows kernel, something that happened with Firefox but had no significant impact with other browsers like Edge or Chrome.