WonderCMS 3.1.3 - 'page' Persistent Cross-Site Scripting

# Exploit Title: WonderCMS 3.1.3 - 'page' Persistent Cross-Site Scripting
# Date: 20-11-2020
# Exploit Author: Mayur Parmar
# Vendor Homepage: https://www.wondercms.com/
# Version: 3.1.3
# Tested on: PopOS

Stored Cross-site scripting(XSS):
Stored attacks are those where the injected script is permanently stored on the target servers,
such as in a database, in a message forum, visitor log, comment field, etc.
The victim then retrieves the malicious script from the server when it requests the stored information.
Stored XSS is also sometimes referred to as Persistent XSS.

Attack vector:
This vulnerability can results attacker to inject the XSS payload in Page keywords and each time any user will visits the website, the XSS triggers and attacker can able to steal the cookie according to the crafted payload.

Vulnerable Parameters: Page Title.

Steps-To-Reproduce:
1. Go to the Simple website builder.
2. Put this payload in Page keywords: Mayur"><img src=x onerror=confirm("XSS")>
3. Now go to the website and the XSS will be triggered.