The WP Directory Kit WordPress plugin before 1.5.5 does not sanitize and escape a parameter before using it in a SQL statement through one of its authenticated AJAX actions, which lacks authorization and nonce checks, allowing any authenticated user such as a Subscriber to perform SQL injection attacks.
https://wpscan.com/vulnerability/6ee8c3b7-5ffe-4b9e-877a-ea3e1924e8d3/