MasterStudy LMS 1.9 - < 3.7.50 - Subscriber+ Membership Plan Quota and Category Restriction Bypass

The MasterStudy LMS WordPress plugin from 1.9 before 3.7.50 does not verify that a course a member asks to enrol in is covered by their membership plan, nor that the plan identifier submitted with the request is one they actually hold, allowing any member to enrol themselves into restricted paid courses outside their plan and beyond the number of courses it entitles them to.