Is yum-security supposed to work on CentOS too, not only on Red Hat? I installed it on a system that has not been updated in quite a while, so I know there are security updates for it, but it does not list any security-related updates:
# yum list-sec Loading "security" plugin Loading "installonlyn" plugin Loading "protectbase" plugin Setting up repositories Reading repository metadata in from local files 0 packages excluded due to repository protections list-sec done # yum --security check-update Loading "installonlyn" plugin Loading "security" plugin Setting up repositories Reading repository metadata in from local files Excluding Packages in global exclude list Finished Limiting package lists to security relevant ones No packages needed, for security, 128 available #