User Registration & Membership < 5.2.8 - Unauthenticated User Data Disclosure via Membership Thank You Page

The User Registration & Membership WordPress plugin before 5.2.8 does not verify that the visitor requesting its membership confirmation page owns the account named in the request, nor that any registration or purchase has taken place, allowing unauthenticated users to retrieve another user's email address, profile fields, role and membership order details. Exploitation requires the site owner to have added a user smart tag to that page's configurable message, which the shipped default does not contain.