WordPress Plugin Picture Gallery 1.4.2 - 'Edit Content URL' Stored Cross-Site Scripting (XSS)

# Exploit Title: WordPress Plugin Picture Gallery 1.4.2 - 'Edit Content URL' Stored Cross-Site Scripting (XSS)
# Date: 2021-08-06 
# Exploit Author: Aryan Chehreghani
# Software Link: https://wordpress.org/plugins/picture-gallery/
# Version: 1.4.2
# Tested on: Windows 10

How to Reproduce this Vulnerability:

1. Install WordPress 5.8
2. Install and activate  Picture Gallery - Frontend Image Uploads, AJAX Photo List
3. Navigate to admin menu wrap >> Picture Gallery >> Options >> Access Control Tab >> enter the XSS payload into the Edit Content URL 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>