Private Message PHP Script 2.0 - Cross-Site Scripting

# Exploit Title:  Private Message PHP Script 2.0 - Persistent Cross-Site scripting
# Date: 2018-05-20
# Exploit Author: Borna nematzadeh (L0RD)
# Vendor Homepage: https://codecanyon.net/item/private-message-php-script/21027192?s_rank=1
# Version: 2.0
# Tested on: Windows

# Description :
Private Message PHP Script 2.0 suffers from persistent cross site scripting.
You can put your malicious javascript payload .
When target opens your massege ,  payload will be executed before self destruction .

# POC :
1) Put this payload into textarea and click submit :
</textarea><script>alert(document.cookie)</script>

2) You will get a link which your javascript code is inside this link . You can send this link to anyone .
3) After clicking on "show me the message" , payload will be executed .