Essential Real Estate < 5.3.5 - Customer+ Arbitrary Paid Package Activation and Forged Paid Invoice via ere_free_package_ajax

The Essential Real Estate WordPress plugin before 5.3.5 does not verify, in one of its AJAX actions, that a listing package selected for free activation is genuinely free or that the requesting user is entitled to it, allowing a self-registered customer to activate a paid package without payment and cause the site to record a paid invoice at the package's full price.