ORA-00600 argument description
You are facing a bug. You need to gather more information using RDA in order to perform an in-depth analysis.

These are known bugs related to your ORA-600 message. 

10043021    11.2.0.4, 12.1.0.1  ORA-600 [kcbnew_3] after select / analyze on RECYCLEBIN object

17586955    11.2.0.4.4, 11.2.0.4.BP11   ORA-600 [ktspfmdb:objdchk_kcbnew_3] in RAC

12747437    11.2.0.3.8, 11.2.0.3.BP21, 11.2.0.4, 12.1.0.1   ORA-600 [ktspfmdb:objdchk_kcbnew_3] after purging single consumer queue table

12323180    11.2.0.2.7, 11.2.0.2.BP17, 11.2.0.3, 12.1.0.1   ORA-600 [ktspfmdb:objdchk_kcbnew_3] due to re-used block read into cache

11902008    11.2.0.4, 12.1.0.1  SMON may crash with ORA-600 [kcbgcur_3] or ORA-600 [kcbnew_3] during Transaction recovery

10137834    11.2.0.2    ORA-600 running DBMS_XDB.MOVEXDB_TABLESPACE

9456964     11.2.0.2    OERI[kcbnew_3] after shrinking an IOT and reusing the blocks freed by shrink


Look if any of the above descriptions matches your case.

But the short answer would be to open a Service Request with Oracle Support.