Microsoft plans to issue 12 security bulletins on 12 February, including seven fixes for vulnerabilities rated as 'critical'.

The security fixes will be released next week on Microsoft's scheduled Patch Tuesday monthly update.

Seven patches address 'critical' vulnerabilities that could allow an attacker to remotely execute code. Three address issues in Office, one in Internet Explorer and the remaining three in Windows.

At least one of the 'critical' flaws in Office also affects Mac OS X users.

Five additional bulletins are rated 'important' by Microsoft. These include two denial of service vulnerabilities in Windows, a Windows user elevation privilege flaw and remote code execution vulnerabilities in Office and Windows.

Microsoft often patches multiple vulnerabilities and software versions with a single bulletin, so the exact number of flaws addressed in the update will not be known until the update is released on Tuesday.