For the third time this year, Microsoft has issued a record-setting security patch.

The company's December Bulletin Release includes 17 security bulletins addressing 40 vulnerabilities in Microsoft Office, Windows, Internet Explorer, SharePoint Server and Exchange.

It was only in October that Microsoft set the record it just broke, with 16 security bulletins. There were however fewer individual vulnerabilities this month than in October (49). And it was two months earlier, in August, that the company had set its previous record, with 14 bulletins to address 34 vulnerabilities.

The huge October patch was supposed to front-load the task of patching so that IT administrators had a lighter schedule over the holidays. So much for that idea.

At least the December crop of bulletins brings only two "critical" ones. Fourteen are rated "important" and one is rated "moderate."

The two critical bulletins, MS10-090 and MS10-091, addressing vulnerabilities in Internet Explorer and Windows respectively, should be deployed first, according to Microsoft.

Microsoft says that has issued 106 bulletins in 2010. That's up substantially from 74 in 2009 and 78 in 2008. According to Symantec, Microsoft patched 261 vulnerabilities in 2010, far beyond its previous record of 170 in 2009. McAfee puts the count at 266.

Joshua Talbot, security intelligence manager for Symantec Security Response, said in an e-mailed statement that the most notable patch is the fix for the fourth zero-day vulnerability utilized by Stuxnet. He also said that the cumulative patch for Internet Explorer should be regarded as a high-priority fix.

Dave Marcus, director of security research and communications at McAfee Labs, said in an e-mailed statement that while the number of critical vulnerabilities is low, the larger number of vulnerabilities overall, from Microsoft and from vendors like Adobe and Oracle, indicate that the threat landscape is broadening, making its even more important for organizations to patch.