Someone can be "jinxed". A "jinx" is a kind of curse, or spell from a witch or voodoo practitioner which means that bad things keep happening. "I must be jinxed" "You're jinxed". It's said in the UK at least. If you just have a lot of accidents, you are "accident-prone" i.e. at risk of having lots of accidents.

It never rains, it pours.

You could also say that the person is 'having a run of bad luck'.

He has been plagued with misfortune.

... or happened..