Secunia says that over one-quarter of applications on users' PCs lack the necessary patches released by software vendors to address critical issues.

Media players seem to be the most commonly vulnerable, with over 33 percent of all Quicktime, and 27 percent of Winamp installations missing important security updates. Browsers do better, with a little over five percent of Firefox, 5.4 percent of IE7, 9.6 percent of IE6, and nearly 12 percent of all Opera 9 installs missing security updates.

The data was culled through anonymous data provided by Secunia's Software Inspector, an online tool that scans a user's computer to ensure applications have the latest security updates for installed applications. The program has been used over 350,000 times.

Secunia said that it believes the percentages of unpatched Microsoft applications are relatively low because of the knowledge of its regular Patch Tuesday program. But it appears with other applications that computer users wait an extended period of time to patch problems.

"This constitutes a significant problem because many of those applications, like WinAMP and Quicktime, are readily used whenever users encounter media files of various kinds," Secunia's Jakob Balle said, noting it would only take one bad QuickTime video to cause trouble with a lot of people.

Balle noted that similar vulnerabilities are also a serious issue in the corporate sector. "Corporations have much more to lose than just their credit card details; there's client lists, design blueprints, employee information, and more at stake," he said.