static struct sctp_transport *sctp_addr_id2transport(struct sock *sk,
					      struct sockaddr_storage *addr,
					      sctp_assoc_t id)
{
	struct sctp_association *addr_asoc = NULL, *id_asoc = NULL;
	struct sctp_af *af = sctp_get_af_specific(addr->ss_family);
	union sctp_addr *laddr = (union sctp_addr *)addr;
	struct sctp_transport *transport;

	if (!af || sctp_verify_addr(sk, laddr, af->sockaddr_len))
		return NULL;

	addr_asoc = sctp_endpoint_lookup_assoc(sctp_sk(sk)->ep,
					       laddr,
					       &transport);

	if (!addr_asoc)
		return NULL;

	id_asoc = sctp_id2assoc(sk, id);
	if (id_asoc && (id_asoc != addr_asoc))
		return NULL;

	sctp_get_pf_specific(sk->sk_family)->addr_to_user(sctp_sk(sk),
						(union sctp_addr *)addr);

	return transport;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.