WordPress Plugin KN Fix Your Title 1.0.1 - 'Separator' Stored Cross-Site Scripting (XSS)

# Exploit Title: WordPress Plugin KN Fix Your Title 1.0.1 - 'Separator' Stored Cross-Site Scripting (XSS)
# Date: 19/07/2021
# Exploit Author: Aakash Choudhary
# Software Link: https://wordpress.org/plugins/kn-fix-your/
# Version: 1.0.1
# Category: Web Application
# Tested on Mac

How to Reproduce this Vulnerability:

1. Install WordPress 5.7.2
2. Install and activate KN Fix Your Title
3. Navigate to Fix Title under Settings Tab >> Click on I have done this and enter the XSS payload into the Separator input field.
4. Click Save Changes.
5. You will observe that the payload successfully got stored into the database and when you are triggering the same functionality at that time JavaScript payload is executing successfully and we are getting a pop-up.
6. Payload Used: "><script>alert(document.cookie)</script>