void sctp_sock_rfree(struct sk_buff *skb)
{
	struct sock *sk = skb->sk;
	struct sctp_ulpevent *event = sctp_skb2event(skb);

	atomic_sub(event->rmem_len, &sk->sk_rmem_alloc);

	/*
	 * Mimic the behavior of sock_rfree
	 */
	sk_mem_uncharge(sk, event->rmem_len);
}

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.