User Registration WordPress Plugin Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the User Registration plugin for WordPress, affecting all versions through 4.2.4. The issue arises from inadequate input sanitization and output escaping on user-supplied attributes within the 'urcr_restrict' shortcode. This vulnerability allows authenticated attackers with contributor-level access or higher to inject arbitrary web 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 'urcr_restrict' shortcode without proper sanitization. This can be done by injecting a script into the shortcode attributes, which will then be executed when the page is viewed.

Remediation

Users are advised to update the User Registration plugin to version 4.3.0 or later, where this vulnerability has been patched.