Hi,
when executing grant command on db2 v9.5 database does not check if that user exists on system. For example if user is not set at time of grant and then sysadmin creates new user with the same userid then that user can get unattented privilages.

Is there any way to tell DB2 to check if user exists when grant is executed?
Regards

You are right in your observation. This has been the case always. AFAIK, you cannot check the existence of a user or group at the time of GRANT.