Oksana Grigorieva went to her lawyer's office today ... before the judge called the attorneys on both sides into court for a closed hearing.
The judge wants to know who leaked the tapes. TMZ has learned ... if the judge traces the leaked Mel Gibson tapes to Oksana ... it could have an impact on her rights with respect to the custody order -- an order that has financial ramifications.
Oksana was prohibited under a restraining order from releasing the tapes or otherwise disseminating the information.
The lawyers are still in court.