If you are asking if the bike will explode or something and if you will have a big a ss accident in a near future?? the answer is no. The worse it could happen is that the cup will crack somewhere else and might get a piece out of it but the bike wont explode at all if that's worrying you. The worse it could happen is that the steering will get lose because of a chunk fell of or something and in that case you will be able to get back home just ride slow and dont do any jumping trick with the bike aswell
Why cracked? My best guess is that the thing got a manufacturing problem or that frame needs to go to the shop to get the top and botton headtube chased before you put a new headset in.
Ck Should RMA that, call them man they sure will send you a new cup and bearings but please get the headtube chased before installing anything. If they dont rma it try to find an old shimano ultegra or 105 with sealed bearings, that will last you maybe more than a CK. Not as light but super reliable.