Xwiki CMS 12.10.2 - Cross Site Scripting (XSS)

# Exploit Title: Xwiki CMS 12.10.2 - Cross Site Scripting (XSS)
# Date: 17-01-2021
# Exploit Author: Karan Keswani
# Vendor Homepage: https://www.xwiki.org/xwiki/bin/view/Main/WebHome
# Software Link: https://www.xwiki.org/xwiki/bin/view/Download/
# Version: Xwiki CMS- 12.10.2
# Tested on: Windows 10

# Description: XWiki 12.10.2 allows XSS via an SVG document to the upload feature of the comment section.

# Additional Information:
Well I found this vulnerability in Xwiki project based websites but they did not respond so i installed a latest version of Xwiki CMS and hosted on localhost with help of Wamp and then i exploited that vulnerability.

# Attack Vector:
1) Create 2 accounts:- 1)Victim & 2)Attacker
2) Login with victim account, there is a option to create new dashboard and there is page says give title and type.( Type of Dashboard:-I created simple page)
3) Now save view the page,
4) Now login with attacker account and search and open the dashboard which has been created by victim,
5) When you open the dashboard there is a comment section option, Go to that comment section & add a comment,there is a upload functionality,
6) So i tried to upload a sample svg file to check that it will allow to upload .svg format
7) Now i created a text file with XSS payload and then saved it as a .svg format
8) Upload your .svg file and click on send it to the server and click ok (your comment will be add)
9) Now open that comment with the victim account and click on that view image you'll see the xss pop-up.

Xss Payload:-
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<svg

onload="alert('xss')"
 xmlns="http://www.w3.org/2000/svg">
</svg>