Microsoft will release nine bulletins to address 21 vulnerabilities in Windows, Office, Internet Explorer and .NET/Silverlight on its next Patch Tuesday.

Scheduled to be released on 14 February, the load will include four critical patches for Windows, Internet Explorer and .NET/Silverlight, while the remaining five patches will be rated as important and affect Windows and Office.

Andrew Storms, director of security operations at nCircle, said: “Microsoft is planning to deliver a big ‘Valentine' next Tuesday. Their advance notification indicated they plan to release nine bulletins and 21 CVEs next Tuesday; this is very consistent with February 2011's ‘Valentine delivery' that included 12 bulletins and 22 CVEs.

“It's surprising that this month's patch affects almost every Windows operating system, each OS is affected by five of the eight applicable bulletins. That's kind of weird because newer OS versions are generally more secure.

“It's even more surprising that Windows Server 2008 R2 is affected by the greatest number of bulletins. Generally, we see fewer bugs on server-side operating systems and this is doubly true for Server 2008 since so many of its newer mitigations and default settings protect the OS even when bugs are found.”

Paul Henry, security and forensic analyst at Lumension, said: “IT continues to benefit from Microsoft's security initiatives in 2012 with comparatively lower numbers year on year. This month, IT should prioritise the four critical bulletins first as all of them likely require a restart.

“The light patch load from Microsoft does not mean IT can sit back and relax, however. A significant patch update from Oracle came out recently and, as always, threats targeting Java must be addressed.”

Wolfgang Kandek, CTO of Qualys, said the critical update to Internet Explorer should be highest priority, especially as attackers are quickly incorporating browser-based attacks into their toolkits; with an exploit for MS12-004 detected 15 days after Patch Tuesday.

“There are also two critical fixes for Windows itself, plus one for the .NET framework that should be prioritised. In the 'important' category, there are three Remote Code Execution vulnerabilities, one of them in Office. Most likely we are looking at file-based attacks and at least the Office vulnerability should be included in your first tier of patching,” he said.