PUBLIC has been granted unnecessary privileges.
I recently finished 12.2.3 to 12.2.9 EBS upgrade. Right after the upgrade, it shows some security recommendations. One of them is "PUBLIC has been granted unnecessary privileges. You should revoke unnecessary privileges from PUBLIC"
DETAILS: Object which is granted INDEX privilege to PUBLIC (format: Table name[Owner]) - ^M
XX_TABLE1[CUSTOMSCHEMA], XX_table2[CUSTOMSCHEMA], XX_table3[CUSTOMSCHEMA], XX_table4[CUSTOMSCHEMA], XX_table5[CUSTOMSCHEMA],^M
Currently in our EBS I see over 32k object privileges assigned to the PUBLIC user.
https://docs.oracle.com/cd/E26401_01/doc.122/e22952/T156458T663583.htm <-- this note says You should revoke unnecessary privileges from the PUBLIC role. Oracle E-Business Suite database objects should not have privileges granted to the PUBLIC role. Any privileges granted to the PUBLIC role from Oracle E-Business Suite objects should be revoked.