Ultimate Member WordPress plugin vulnerabilities

The Ultimate Member WordPress plugin before version 2.6.7 does not prevent visitors from creating user accounts with arbitrary capabilities, effectively allowing attackers to create administrator accounts at will.

The Ultimate Member WordPress plugin before version 2.13.0 does not validate a submitted role selection when it cannot resolve the set of roles a profile form permits, and screens the value against the site's registered role names rather than against the form's own allow-list. This allows unauthenticated users who register through the plugin's own form to grant themselves arbitrary capabilities and reach administrator-equivalent access.

The Ultimate Member plugin for WordPress in versions up to and including 2.11.0 is vulnerable to Stored Cross-Site Scripting via the plugin's shortcode attributes due to insufficient input sanitization and output escaping. This allows authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts into pages.