CentOS check and install available security updates

1. To install the yum-security plugin

yum install yum-plugin-security

2. To list all available security updates without installing them

yum updateinfo list sec available

To get the count

yum updateinfo list sec available | wc -l

3. To install available security updates

yum -y update --security

To only install the packages that have a security errata use

yum update-minimal --security -y

To install a security update using a CVE reference

yum update --cve <CVE> (e.g. yum update --cve CVE-2008-0947)

Refer to:
https://access.redhat.com/solutions/10021
https://www.thegeekdiary.com/centos-rhel-6-how-to-list-or-install-only-security-updates-with-yum/