GHSA-H698-R4HM-W94P Validation Bypass in paypal-ipn

Versions 2.x.x and earlier of paypal-ipn are affected by a validation bypass vulnerability. paypal-ipn uses the testipn parameter which is set by the PayPal IPN simulator to determine if it should use the production PayPal site or the sandbox. A motivated attacker could craft a request string usi...