The DBA_ROLE_PRIVS view provides information on all roles that have been granted to users. A row is created for each role to which a user has been granted.

granteeTEXTUser name to whom the role was granted.
granted_roleTEXTName of the role granted to the grantee.
admin_optionTEXTYES if the role was granted with the admin option, NO otherwise.
default_roleTEXTYES if the role is enabled when the grantee creates a session.