The Membership & Content Restriction – Paid Member Subscriptions WordPress plugin before 2.4.2 did not sanitise, validate or escape its order and orderby parameters before using them in SQL statement, leading to Authenticated SQL Injections in the Members and Payments pages.
https://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=29172
https://wpscan.com/vulnerability/2277d335-1c90-4fa8-b0bf-25873c039c38
https://plugins.trac.wordpress.org/changeset/2566399/paid-member-subscriptions