The Eventin WordPress plugin before 4.1.24 does not properly authorise order finalisation when its offline (local) payment method is enabled, relying on a nonce that is exposed to unauthenticated vi…

Summary

The Eventin WordPress plugin before 4.1.24 does not properly authorise order finalisation when its offline (local) payment method is enabled, relying on a nonce that is exposed to unauthenticated visitors and never checking that the caller owns the order, allowing unauthenticated attackers to reset any existing order and its attendees to a pending state and thereby invalidate paid tickets.