The nearness of IoT (Internet of Things) gadgets in everyday life these days is expanding, each of us owning at slightest one IoT gadget. Therefore, the adoption of this technology is as global as possible and spread on a very large scale throughout the civilized world. Utilizing IoT gadgets most of the time on a day-by-day premise, we end up doing nearly any action with their offer assistance, as we also make online payments through different web or mobile applications, or specifically with the phone/smartwatch at physical portable POS (Point of Sale). For people, this possibility of carrying out financial transactions online is no longer a novelty, but we must indicate the fact that these exchanges are attempted through a mediator, specifically the issuing Bank of each client. Regarding financial transactions, the novelty exists when we talk about making them with cryptocurrencies, so using the same smart or IoT devices to make payments, but this time we no longer do them through an intermediary, i.e., the Bank, we do them directly on the so-called blockchain. The main purpose of this paper is to cover a brief overlook of how these financial transactions made on blockchain through IoT devices are vulnerable from a cybersecurity point of view.