vbulletin 3.8.6 cookie security hole

[kh99]

Originally Posted by Max Taxable

And since there was no way to read the source code, no real way to tell what all was in the file.

OK, but how is that a security hole (and what does it have to do with cookies)? Maybe if they are saying that someone was able to upload a php file as an image, then run it by putting it in an IMG tag? (No, that doesn't make sense, you could run it without the img tag).