The Mail logging – WP Mail Catcher plugin for WordPress is vulnerable to Stored Cross-Site Scripting via PHPMailer 'wp_mail_failed' Error Message in all versions up to, and including, 2.1.12 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Successful exploitation requires a separately installed plugin, such as Contact Form 7, that passes unauthenticated user-controlled input into mail fields whose content PHPMailer will include in its failure error message.