Elementor Addon Elements < 1.11.2 - Contributor+ Stored XSS

Description

The “Elementor Addon Elements” WordPress Plugin before 1.11.2 has several widgets that are vulnerable to stored Cross-Site Scripting (XSS) by lower-privileged users such as contributors, all via a similar method.

The “Flip Box” widget accepts a “front_title_html_tag” parameter. Although the element control lists a fixed set of possible html tags, it is possible to send a ‘save_builder’ request with the “front_title_html_tag” set to JavaScript. Alternatively, it is possible to set “front_title_html_tag” to simply “script” and add the JavaScript to be executed in the “front_title” parameter.
This JavaScript will then be executed when the saved page is viewed or previewed. The “back_title_html_tag” parameter appears to be vulnerable to the same exploit.

We’ve verified that the Price Table widget is similarly vulnerable via the "heading_tag" and "sub_heading_tag" parameters, and the following widgets are likely also vulnerable to similar exploits:
Split Text: "title_size" parameter containing JS
Text Separator: "html_tag" containing JS or set to "script" with actual JS to be executed in "title" parameter
Timeline: "html_tag" parameter containing JS

These vulnerabilities are nearly identical to the vulnerabilities we have recently disclosed in the main Elementor plugin: https://www.wordfence.com/blog/2021/03/cross-site-scripting-vulnerabilities-in-elementor-impact-over-7-million-sites/