Membership Plugin Restrict Content Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the Membership Plugin – Restrict Content for WordPress, affecting all versions through 3.2.15. The issue arises from inadequate input sanitization and output escaping of user-supplied attributes in the plugin's 'register_form' and 'restrict' shortcodes. This vulnerability allows authenticated attackers with contributor-level access and above to inject arbitrary scripts into pages, which are executed when users access the affected pages.

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 'register_form' or 'restrict' shortcodes to inject scripts. The injected scripts will be executed when the page is accessed by any user.

Remediation

Users are advised to update the plugin to version 3.2.16 or a newer patched version.