The WPBakery Visual Composer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the link attribute within the vc_single_image shortcode in all versions up to, and including, 7.6 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

An AJAX action registered by the WPBakery Page Builder (Visual Composer) Clipboard WordPress plugin before 4.5.6 did not have capability checks nor sanitization, allowing low privilege users (subscriber+) to call it and set XSS payloads, which will be triggered in all backend pages.

An AJAX action registered by the WPBakery Page Builder (Visual Composer) Clipboard WordPress plugin before 4.5.8 did not have capability checks, allowing low privilege users, such as subscribers, to update the license options (key, email).