How common are XSS holes?
Cross site scripting holes are gaining popularity among hackers as easy holes to find in large websites. Websites from FBI.gov, CNN.com, Time.com, Ebay, Yahoo, Apple computer, Microsoft, Zdnet, Wired, and Newsbytes have all had one form or another of XSS bugs. Every month roughly 10-25 XSS holes are found in commercial products and advisories are published explaining the threat.