The WP Maps WordPress plugin before 4.9.8 does not perform a capability check, nor validate a nonce, in one of its AJAX actions, allowing users with a Subscriber account to create an unlimited number of options in the database, each of which is loaded on every page request.
https://wpscan.com/vulnerability/2e12d9cf-520a-4602-aeee-7dbc26f79951/