Well, I tested this forums security with some major and minor php injections, xss injections, and other code injections as well. The page returned to the index no matter where I was and no information was revealed, nothing even hidden or in a link.
But, it didn't do a perfect job into always taking me back to the index as it should, sometimes it loaded the page for a long time and then said that the page cannot be found.
Overall, I rate this website's code injection security a 9.6 of 10. (although - I haven't used every injection possible...just the major and popular ones, and some of the minor ones that are good)