5F50

Issuer URL is a web address the card carries pointing to the issuer's own resource library - content meant for card personalization and management workflows rather than for anything the payment transaction itself needs, related to the IBAN (5F53) and BIC (5F54), both covered alongside it here, as part of the same small cluster of banking-identity data EMV allows a card to carry for administrative purposes beyond the core payment flow. None of these three fields participate in authorization, cryptogram computation, or CVM logic in any way - a terminal that doesn't recognise or doesn't populate 5F50 hasn't broken anything about the transaction itself, since this data exists for out-of-band card-management tooling to consume, not for the terminal's own transaction-processing logic. A card management system that does consume 5F50 needs ordinary URL validation and handling discipline, since it's carrying a value from the card that will be dereferenced by whatever system reads it, the same general caution that applies to any URL sourced from an external, potentially untrusted input. See EMV 4.4 Book 3.