lseg_recv(PG_FUNCTION_ARGS)
{
	StringInfo	buf = (StringInfo) PG_GETARG_POINTER(0);
	LSEG	   *lseg;

	lseg = (LSEG *) palloc(sizeof(LSEG));

	lseg->p[0].x = pq_getmsgfloat8(buf);
	lseg->p[0].y = pq_getmsgfloat8(buf);
	lseg->p[1].x = pq_getmsgfloat8(buf);
	lseg->p[1].y = pq_getmsgfloat8(buf);

#ifdef NOT_USED
	lseg->m = point_sl(&lseg->p[0], &lseg->p[1]);
#endif

	PG_RETURN_LSEG_P(lseg);
}

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