I checked out the website and the
full report as well. The report concentrated mostly on web application technologies and their respective implementations as it mentioned a lot about SQL injection and cross-site scripting (XSS). These are browser independent as they have to do with the code written for the web application and not for any specific browser. Any browser is just as susceptible to these attacks.
I couldn't find much about vulnerabilities that affect the browser. They have a single page dedicated to the topic (page 12) out of the entire 22 page document. It's just a small blurb of about 100 words and a huge graph to take up the rest of the page. They have no discussion on the vulnerabilities they found for each browser, or even how they tested for them. It's just a blurb stating some statistic. They give no evidence. I didn't' even see a mention of version numbers for each browser. There are vast amounts of people still using IE 6. There are many who use IE 8. While they are part of the same browser family, they are vulnerable to very different attacks essentially making them two completely separate browsers. You would think that if they went into such detail in web application vulnerabilities, they would go into at least a little bit of detail for vulnerabilities that affect the browser.
If we were to say that SQL Injection and XSS attacks were still at large based off the findings of this report, that would be a reasonable claim to make. However, given the inadequacy of information given about actual
browser vulnerabilities, I don't think its a fair claim to make that Firefox and Safari are more vulnerable than IE. This report may have spoken a lot about the state of web applications, but it has changed nothing as far as browsers themselves go.
Let me know if I missed something in that report though

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