Oracle My Oracle Support - MOS
Create a service request (SR):
You will need a support contract with Oracle to be able to create an SR.
Is "it" definitely a bug? You could post symptoms here to enable other posters to possibly help with work around/s (if any), advice on whether it really is a bug, etc.
On My Oracle Support, if you have a support identifier. You should have a support identifier if you are paying for database support.
Otherwise you can mention it here, but it is not guaranteed to be picked up.