@Tinkode, I don't know whether you are the author of the vulnerability but I think it's more ethical to report it before post it. Just a sugerence. I tell you this because youtube offer a fairly good services for free, as well as google, and this kind of stuffs doesn't benefit them at all. I'd have reported rather than divulge it all around the www. Anyway, very good job! How did you reach to the security hole?