WPBakery Page Builder Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the WPBakery Page Builder plugin for WordPress, affecting all versions through 8.6.1. The issue arises from inadequate restrictions on allowed HTML tags and improper sanitization of user-supplied attributes in the 'font_container' parameter of the 'vc_custom_heading' shortcode. This vulnerability allows authenticated attackers with contributor-level access or higher to inject arbitrary scripts into posts, which are executed when a user views the injected page with the malicious shortcode attributes.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the page.

Reproduction

To reproduce this vulnerability, an authenticated user with contributor-level access or higher can use the 'vc_custom_heading' shortcode. By injecting malicious scripts into the 'font_container' parameter without proper sanitization, these scripts will be executed when the post is viewed.

Remediation

Users are advised to update WPBakery Page Builder to version 8.7 or a newer patched version.