No browser ever wants to find themselves at the top of the Internet vulnerability heap, but it appears as if that dubious distinction falls this year on Mozilla Firefox, which beat out Apple’s Safari browser by 9% (44% to 35%). Last year it was Microsoft’s Internet Explorer that topped the list, edging Firefox 43% to 39%.

Much of the reason for Firefox’s vulnerability has to do with the plug-ins that the browser allows. The browser has made a number of moves this year to boost plug-in security, but the efforts have for the most part proven futile. According to Lars Ewe, CTO of Cenzic, the company that produced the vulnerability report, Firefox’s plug-ins are somewhat of a catch 22.

“The plug-in architecture that they have is a selling fact for the browser and one of the reasons why I love using it,” Ewe told internetnews.com. They can’t control security aspects of all the plug-ins and the vulnerabilities are a side effect of that.”

Cenzic reported that Opera had the lowest vulnerability rating (6%).

These figures are obviously telling, but it goes without saying that they’re a little skewed. Aside from their plug-in use, Firefox’s traction has grown significantly in recent years. They’re a much more popular site than they used to be, and it’s starting to show in adverse ways. With hackers and virus makers around, it’s usually the case that the more popular you get, the more defense you’ve got to play.