The Ultimate Member – User Profile, Registration, Login, Member Directory, Content Restriction & Membership Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'user_url' parameter in all versions up to, and including, 2.14.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Successful exploitation requires a visitor to click the attacker's Website URL link on their public Ultimate Member profile, a condition that is trivially met since the redirect-confirmation onclick handler is enabled by default on all new installations.