To update installed packages for security on a Red Hat Enterprise Linux (RHEL) 8 or 9 system, you can use the dnf package manager with the --security option.
To update all installed packages for security, run the following command:
sudo dnf update --security
This will update all installed packages that have security updates available.
You can also use the --refresh option to check for new updates and the --assumeyes option to automatically answer "yes" to any prompts:
sudo dnf update --refresh --security --assumeyes
Keep in mind that you will need to have root privileges (or be a member of the sudo group) in order to update packages using dnf.
It is recommended to regularly update your system to ensure that you have the latest security patches and fixes installed. You can use the dnf update command to update all installed packages, or use the --security option to update only packages with security updates.