Flexmonster Pivot Table & Charts 2.7.17 - 'Remote JSON' Reflected XSS

# Exploit Title: Flexmonster Pivot Table & Charts 2.7.17 - 'Remote JSON' Reflected XSS
# Date: 08/01/2020
# Exploit Author: Marco Nappi
# Vendor Homepage: https://www.flexmonster.com/
# Version: Flexmonster Pivot Table & Charts 2.7.17
# Tested on: Flexmonster Pivot Table & Charts 2.7.17
# CVE : CVE-2020-20139

Cross Site Scripting (XSS) vulnerability in the Remote JSON component 

Reflected XSS:
The Reflected XSS is a result of insufficient input sanitization of the 'path' parameter when fetching the file specifications (file_specs.php). Below I have provided an example URL. When using this URL the user navigates to an non-existing file (the XSS payload). This results in the execution of the payload.

payload:
<svg onload=alert("OpenRemoteJSON")><!--