The oradism executable cannot have 755 (rwx-r-x-r-x) permissions, and should be owned by root like other executables in the $ORACLE_HOME/bin directory.
The permissions for oradism must be 4750 with the SetUID bit for the owner, e.g. for 11.2:
1. cd $ORACLE_HOME/bin
2. chown root oradism
3. chmod 4750 oradism
4. bounce the database