The Audio Merchant plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 5.0.4. This is due to missing or incorrect nonce validation on the audio_merchant_save_settings function. This makes it possible for unauthenticated attackers to modify the plugin's settings and inject malicious web scripts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.