Input validation vulnerability in Audio Merchant 5.0.4

The Audio Merchant plugin for WordPress is vulnerable to a type of attack called Cross-Site Request Forgery. This means that if an unauthenticated attacker can get a website administrator to click on a link, the attacker can modify the plugin’s settings and inject malicious code into the website. This affects all versions of the plugin up to version 5.0.4. The issue is caused by a lack of validation on the audio_merchant_save_settings function.