static int sctp_getsockopt_connectx3(struct sock *sk, int len,
				     char __user *optval,
				     int __user *optlen)
{
	struct sctp_getaddrs_old param;
	sctp_assoc_t assoc_id = 0;
	int err = 0;

#ifdef CONFIG_COMPAT
	if (in_compat_syscall()) {
		struct compat_sctp_getaddrs_old param32;

		if (len < sizeof(param32))
			return -EINVAL;
		if (copy_from_user(&param32, optval, sizeof(param32)))
			return -EFAULT;

		param.assoc_id = param32.assoc_id;
		param.addr_num = param32.addr_num;
		param.addrs = compat_ptr(param32.addrs);
	} else
#endif
	{
		if (len < sizeof(param))
			return -EINVAL;
		if (copy_from_user(&param, optval, sizeof(param)))
			return -EFAULT;
	}

	err = __sctp_setsockopt_connectx(sk, (struct sockaddr __user *)
					 param.addrs, param.addr_num,
					 &assoc_id);
	if (err == 0 || err == -EINPROGRESS) {
		if (copy_to_user(optval, &assoc_id, sizeof(assoc_id)))
			return -EFAULT;
		if (put_user(sizeof(assoc_id), optlen))
			return -EFAULT;
	}

	return err;
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.