Apple tops the list of IBM's X-Force security list of most vulnerable vendors followed by Microsoft and Adobe, according to the "International Business Times" (http://macosg.me/2/st). However, Apple is the only major vendor that has patched all critical security flaws in its operating systems.

Apple held the top position for a second year in a row, while Microsoft moved from third to second. Adobe jumped from the ninth position to third on account of recent PDF and Flash-based loopholes like the ones used to jailbreak the iPhone. Linux topped the list of the most vulnerable operating systems.

Apple accounted for 4% of all vulnerability disclosures with Microsoft reporting 3.4%. But when it comes to the least patched vendors, the top three positions are held by Sun, Microsoft and Mozilla with Apple in the fourth place.

The IBM X-Force Trend and Risk Report is produced twice per year: once at mid-year and once at year-end. This report provides statistical information about all aspects of threats that affect Internet security, including software vulnerabilities and public exploitation, malware, spam, phishing, web-based threats, and general cyber criminal activity.