Download Manager < 3.3.72 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'regurl' Shortcode Attribute

Description

The Download Manager plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'regurl' parameter in all versions up to, and including, 3.3.71 due to insufficient input sanitization and output escaping. 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. The injected payload only fires for logged-out site visitors, as the vulnerable login-form.php template branch is gated on !is_user_logged_in(); authenticated users viewing the same page are served a different template and are not affected.