txid_snapshot_send(PG_FUNCTION_ARGS)
{
	TxidSnapshot *snap = (TxidSnapshot *) PG_GETARG_VARLENA_P(0);
	StringInfoData buf;
	uint32		i;

	pq_begintypsend(&buf);
	pq_sendint(&buf, snap->nxip, 4);
	pq_sendint64(&buf, snap->xmin);
	pq_sendint64(&buf, snap->xmax);
	for (i = 0; i < snap->nxip; i++)
		pq_sendint64(&buf, snap->xip[i]);
	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}

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