Windows users often forget to patch their Apple programs
Apple's multimedia program, QuickTime, and its iTunes software were ranked as some of the most "exposed" programs based on risk by Secunia Research, which is now part of Flexera Software.
Among U.S. users, some 61 percent of computers detected running QuickTime did not have the latest version. With iTunes, 47 percent of the installations were outdated versions.
It's not Apple's fault. Although many software companies alert users to new versions of applications, it's largely up to users to install them.
The data was collected between October 2014 through last month from computers running Flexera's Personal Software Inspector, a free tool that checks if all applications are up to date. About 8 million computers have the tool installed.
Outdated software can potentially pose a security risk since unpatched vulnerabilities could be used by hackers to take over a computer. Over the last year, 18 vulnerabilities have been found in QuickTime.
In September, Apple posted an advisory warning of several problems in QuickTime versions prior to 7.7.8 for Windows 7 and Vista after it had patched the issues about a month prior.
One of the flaws could be exploited by crafting a malicious file, which "may lead to an unexpected application termination or arbitrary code execution," Apple said.
Other applications that ranked in the top five most exposed programs included Adobe Reader X 10.x, Oracle Java JRE 1.8.x/8.x and Adobe Reader XI 11.x.
Flexera published its survey results for 14 countries here.