box_add(PG_FUNCTION_ARGS)
{
	BOX		   *box = PG_GETARG_BOX_P(0);
	Point	   *p = PG_GETARG_POINT_P(1);

	PG_RETURN_BOX_P(box_construct((box->high.x + p->x),
								  (box->low.x + p->x),
								  (box->high.y + p->y),
								  (box->low.y + p->y)));
}

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