The vulnerability centers on improper input validation and authorization in the V1/customers/me endpoint. The 'me' endpoint typically maps to the current user, but the issue suggests the system allows substituting or overriding this reference. The controller action (Get::execute) is the entry point for this endpoint and is responsible for input handling. If it passes unvalidated user-supplied parameters (e.g., a manipulated customer ID) to CustomerRepositoryInterface::getById, which lacks authorization checks, attackers can access arbitrary customer data. Both functions are critical to the insecure direct object reference chain described in CWE-639 and CWE-863.