static bool loc_size_ok(uint8_t size) {
        uint8_t m = size >> 4, e = size & 0xF;

        return m <= 9 && e <= 9 && (m > 0 || e == 0);
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.