WordPress Plugin Testimonial Slider and Showcase 2.2.6 - Stored Cross-Site Scripting (XSS)

# Exploit Title: WordPress Plugin Testimonial Slider and Showcase 2.2.6 - Stored Cross-Site Scripting (XSS)
# Date: 05/08/2022
# Exploit Author: saitamang , yunaranyancat , syad
# Vendor Homepage: https://wordpress.org
# Software Link: https://wordpress.org/plugins/testimonial-slider-and-showcase/
# Version: 2.2.6
# Tested on: Centos 7 apache2 + MySQL

WordPress Plugin "Testimonial Slider and Showcase" is prone to a cross-site scripting (XSS) vulnerability because it fails to properly sanitize user-supplied input. An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This can allow the attacker to steal cookie-based authentication credentials and launch other attacks. WordPress Plugin "Testimonial Slider and Showcase" version 2.2.6 is vulnerable; prior versions may also be affected.

Login as Editor > Add testimonial > Under Title inject payload below ; parameter (post_title parameter) > Save Draft > Preview the post

payload --> test"/><img/src=""/onerror=alert(document.cookie)>

The draft post can be viewed using the Editor account or Admin account and XSS will be triggered once clicked.