Kryptonite had a well-publicized issue with their locks which was fixed a while ago....but if you're using a cable lock it won't matter, because the cables themselves are easily defeated by most bike thieves. Additionally, even with a good U-lock or hardened chain, your bike's safety is only as good as the item you've locked the bike to, or if you have a bike thief that is willing to saw through the bike frame and sell off the individual parts.

But using a cable lock only makes it easier for the thief, and it's more likely that your bike will be stolen.