The Quiz Maker plugin for WordPress is vulnerable to SQL Injection via spoofed IP headers in all versions up to, and including, 6.7.0.56 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. This is only exploitable in configurations where the server is set up to retrieve the IP from a user-supplied field like `X-Forwarded-For` and limit users by IP is enabled.