From our official rules page:
2.2 The opening break begins with ball in hand behind the head string. On the break, the cue ball may contact either a cushion or any ball in the rack first, but in either case, after contacting at least one ball, an object ball must be pocketed, or the cue ball or at least one object ball must contact a rail, otherwise it is a one foul penalty. As long as a legal stroke is employed from behind the head string on the break, the incoming player must play the balls where they lie – there are no re-racks for a pocket scratch or failure to contact a cushion or pocket a ball on the break.
So as long as the CB hits a rail after contacting the rack there should be no foul. In straight pool, however, I do think you have to have a ball or 2 hit the rail after the break but don't quote me on that.