Security :: Automatic Generated Grants On Sys_plsql_xxxx_yy_z

in the dba_tab_privs we can find some entries like this:

SELECT *
FROM dba_tab_privs
WHERE GRANTEE IN ('XXXXXXXX')

GRANTEE OWNER TABLE_NAME GRANTOR PRIVILEGE GRANTABLE HIERARCHY
XXXXXXXX YYYYYYYYYYY SYS_PLSQL_71964_26_1 YYYYYYYYYYY EXECUTE YES NO

Those grants were generated automatically by oracle. Is there any way to prevent Oracle to grant them? An external audit-rule tells us not to give any grant directly to user - we always have to use databaseroles.