Accept Stripe Payments < 2.1.4 - Unauthenticated Product Substitution via IDOR

The Accept Stripe Payments WordPress plugin before 2.1.4 does not verify that the product fulfilled when a checkout is completed matches the product the authoritative payment was actually made for, checking only that the amount paid is at least the referenced product's price, allowing unauthenticated attackers who complete a genuine payment to obtain fulfilment for a different, equal- or lower-priced product than the one they paid for.