The Tutor LMS WordPress plugin before 4.0.6 does not validate values used to build a database query, and does not restrict which template file a request may load, allowing unauthenticated users to inject SQL and to read question and answer content belonging to courses that are not publicly available. The injected text reaches the query as grammar rather than as data, and on the database engines tested it does not yield extraction of arbitrary data, so the confidentiality impact is the disclosed course content rather than the database at large.