The login_register plugin for WordPress is vulnerable to Cross-Site Request Forgery to Stored Cross-Site Scripting in all versions up to, and including, 1.2.0. This is due to missing nonce validation on the settings page and insufficient input sanitization and output escaping on the 'login_register_login_post' parameter. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page via a forged request granted they can trick an administrator into performing an action such as clicking on a link.