A group of white-hat hackers has discovered various XSS vulnerabilities on websites belonging to three well-known security companies. The three security firms in question are Symantec, Eset and Panda Security. XSS flaws basically happen because of errors in coding, but one would think that security firms would be especially careful to avoid things like that on their pages.Fortunately, it seems these particular flaws have not been misused before the patching, but this instance should be a lesson for us all.
Source: https://www.helpnetsecurity.com/2010/10/04/xss-flaws-found-on-three-security-firms-websites/