static int ipx_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
{
	struct sock *sk = sock->sk;
	struct ipx_sock *ipxs = ipx_sk(sk);
	DECLARE_SOCKADDR(struct sockaddr_ipx *, usipx, msg->msg_name);
	struct sockaddr_ipx local_sipx;
	int rc = -EINVAL;
	int flags = msg->msg_flags;

	lock_sock(sk);
	/* Socket gets bound below anyway */
/*	if (sk->sk_zapped)
		return -EIO; */	/* Socket not bound */
	if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
		goto out;

	/* Max possible packet size limited by 16 bit pktsize in header */
	if (len >= 65535 - sizeof(struct ipxhdr))
		goto out;

	if (usipx) {
		if (!ipxs->port) {
			struct sockaddr_ipx uaddr;

			uaddr.sipx_port		= 0;
			uaddr.sipx_network	= 0;
#ifdef CONFIG_IPX_INTERN
			rc = -ENETDOWN;
			if (!ipxs->intrfc)
				goto out; /* Someone zonked the iface */
			memcpy(uaddr.sipx_node, ipxs->intrfc->if_node,
				IPX_NODE_LEN);
#endif
			rc = __ipx_bind(sock, (struct sockaddr *)&uaddr,
					sizeof(struct sockaddr_ipx));
			if (rc)
				goto out;
		}

		rc = -EINVAL;
		if (msg->msg_namelen < sizeof(*usipx) ||
		    usipx->sipx_family != AF_IPX)
			goto out;
	} else {
		rc = -ENOTCONN;
		if (sk->sk_state != TCP_ESTABLISHED)
			goto out;

		usipx = &local_sipx;
		usipx->sipx_family 	= AF_IPX;
		usipx->sipx_type 	= ipxs->type;
		usipx->sipx_port 	= ipxs->dest_addr.sock;
		usipx->sipx_network 	= ipxs->dest_addr.net;
		memcpy(usipx->sipx_node, ipxs->dest_addr.node, IPX_NODE_LEN);
	}

	rc = ipxrtr_route_packet(sk, usipx, msg, len, flags & MSG_DONTWAIT);
	if (rc >= 0)
		rc = len;
out:
	release_sock(sk);
	return rc;
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.