# Exploit Title: MyBB Threads to Link Plugin v1.3 - Persistent XSS # Date: 3/15/2018 # Author: 0xB9 # Contact: luxorforums.com/User-0xB9 or 0xB9[at]protonmail.com # Software Link: https://community.mybb.com/mods.php?action=view&pid=1065 # Version: v1.3 # Tested on: Ubuntu 17.10 1. Description: When editing a thread the user is given to the option to convert the thread to a link. 2. Proof of Concept: Persistent XSS - Edit a thread or post you've made - At the bottom of the edit page in the Thread Link box input the following <a """><SCRIPT>alert("XSS")</SCRIPT>"> - Now visit the forum your thread/post exists in to see the alert. 3. Solution: The plugin has since been removed after notifying the author. Patch in line 83: $thread['tlink'] = ($thread['tlink']); to $thread['tlink'] = htmlspecialchars_uni($thread['tlink']);