MyBB My Arcade Plugin 1.3 - Cross-Site Scripting

# Exploit Title: MyBB My Arcade Plugin v1.3 - Persistent XSS
# Date: 2/21/2018
# Author: 0xB9
# Contact: luxorforums.com/User-0xB9 or 0xB9[at]protonmail.com
# Software Link: https://community.mybb.com/mods.php?action=view&pid=411
# Version: 1.3
# Tested on: Ubuntu 17.10


1. Description:
The My Arcade plugin adds a page of arcade games and keeps track of user scores, also allowing users to add a comment next to their score. The comment box is vulnerable to a persistent XSS.
 

2. Proof of Concept:

Persistent XSS
- Play an arcade game
- Add the following comment to your score <p """><SCRIPT>alert("XSS")</SCRIPT>">
- Edit the comment, Boom.


3. Solution:
Update to 1.3.1
Patch: https://github.com/PaulBender/My-Arcade/commit/4ee2a2e8d245defb94930c2c377e78ddfb0fcc94