The AppMySite – WordPress & WooCommerce Mobile App Builder (No-Code Android & iOS App Maker) plugin for WordPress is vulnerable to Stored Cross-Site Scripting via save_ams_license_key AJAX Handler in all versions up to, and including, 3.15.3 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. The save_ams_license_key AJAX handler performs no capability check and no nonce verification, meaning any authenticated user with Subscriber-level access or above can invoke it to store the malicious payload.