        SERVICE_REQUEST: (p, service) => {
          if (exchanges === 0
              || acceptedAuthSvc
              || this.authenticated
              || service !== 'ssh-userauth') {
            proto.disconnect(DISCONNECT_REASON.SERVICE_NOT_AVAILABLE);
            socket.end();
            return;
          }

          acceptedAuthSvc = true;
          proto.serviceAccept(service);
        },
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.