static u64 dccp_ack_seq(const struct dccp_hdr *dh)
{
	const struct dccp_hdr_ack_bits *dhack;

	dhack = (void *)dh + __dccp_basic_hdr_len(dh);
	return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
		     ntohl(dhack->dccph_ack_nr_low);
}

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.