Here http://php.net/manual/en/ref.pdo-cubrid.php it says:
PDO_CUBRID supports both autocommit_mode and transaction, and autocommit_mode is disabled by default. You can use PDO::setAttribute() to change its state.
Why? Since 8.4.0 auto commit mode in CUBRID was enabled by default. Is it just wrong information in the manual or the driver hasn't been changed?