Wordpress Theme Wibar 1.1.8 - 'Brand Component' Stored Cross Site Scripting

# Exploit Title: Wordpress Theme Wibar 1.1.8 - 'Brand Component' Stored Cross Site Scripting
# Date: 11/27/2020
# Exploit Author: Ilca Lucian Florin
# Vendor Homepage: http://demo.themeftc.com/wibar
# Software Link: https://themeforest.net/item/wibar-responsive-woocommerce-wordpress-theme/20994798
# Version: 1.1.8
# Tested on: Latest Version of Desktop Web Browsers: Chrome, Firefox, Microsoft Edge

The WordPress theme contains Brands feature which is vulnerable to stored
cross site scripting. The logo URL parameter is vulnerable to cross site
scripting. The following vector was used for testing XSS: "><script
src="data:;base64,YWxlcnQoZG9jdW1lbnQuZG9tYWluKQ=="></script>.

In order to reproduce the vulnerability, please follow the next steps:

1. Log in as editor/administrator/contributor/author:
https://website.com/wp-admin
2. Go to Brands section
3. Click add new brand and add a custom brand title
4. The vulnerable parameter is: Logo URL / <input type="text"
name="ftc_brand_url" id="ftc_brand_url" value="">
5. Add the following payload: "><script
src="data:;base64,YWxlcnQoZG9jdW1lbnQuZG9tYWluKQ=="></script> , where
base64 == alert(document.domain)
6. Publish
7. The alert will pop up when a user will visit the website on
https://website.com/brand/vulnerablebrand.

Evidence:

1. https://ibb.co/1fpYJWN
2. https://ibb.co/S7j5Sgd

C.V.S.S Score: CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:L / 7.5 High