The Quiz Maker Business, Developer, and Agency plugins for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the 'ays_save_google_credentials' function in all versions up to, and including, 8.8.0 (Business), up to, and including, 21.8.0 (Developer), and up to, and including, 31.8.0 (Agency). This makes it possible for unauthenticated attackers to modify the Google Sheets integration credentials within the plugin's settings. Because the 'client_id' parameter is not sanitized or escaped when used in output, this vulnerability could also be leveraged to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.