QTNBinary(QTNode *in)
{
	int			i;

	/* since this function recurses, it could be driven to stack overflow. */
	check_stack_depth();

	if (in->valnode->type != QI_OPR)
		return;

	for (i = 0; i < in->nchild; i++)
		QTNBinary(in->child[i]);

	if (in->nchild <= 2)
		return;

	while (in->nchild > 2)
	{
		QTNode	   *nn = (QTNode *) palloc0(sizeof(QTNode));

		nn->valnode = (QueryItem *) palloc0(sizeof(QueryItem));
		nn->child = (QTNode **) palloc0(sizeof(QTNode *) * 2);

		nn->nchild = 2;
		nn->flags = QTN_NEEDFREE;

		nn->child[0] = in->child[0];
		nn->child[1] = in->child[1];
		nn->sign = nn->child[0]->sign | nn->child[1]->sign;

		nn->valnode->type = in->valnode->type;
		nn->valnode->qoperator.oper = in->valnode->qoperator.oper;

		in->child[0] = nn;
		in->child[1] = in->child[in->nchild - 1];
		in->nchild--;
	}
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.