All versions of e107 have a vulnerability that allows html tags and content to be posted to the stats page and to be listed under Referers. This allows an attacker to put any site link or code they want on the list of Referers.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/33389/e107flaw.txt
Source: https://packetstormsecurity.com/files/33389/e107flaw.txt.html