RHEL / CentOS: yum Lists / Installs Only Security Updates

How do I only list or install only security updates under RHEL 5.x or CentOS Linux server? How do I find out security updates descriptions such as CVE, bugs, issued date and type for each patch?

You can easily find out security patches related information using yum-security plugin. This plugin adds the options --security, --cve, --bz and --advisory flags to yum and the list-security and info-security commands. The options make it possible to limit list/upgrade of packages to specific security relevant ones. The commands give you the security information.

Install Plugin

Type the following command:
# yum install yum-security

How Do I Display Available Security Updates?

Type the following command:
# yum list-security
Sample Outputs:

Loaded plugins: rhnplugin, security
RHSA-2009:1148-1 security httpd-2.2.3-22.el5_3.2.x86_64
RHSA-2009:1148-1 security httpd-devel-2.2.3-22.el5_3.2.i386
RHSA-2009:1148-1 security httpd-manual-2.2.3-22.el5_3.2.x86_64
RHSA-2009:1148-1 security mod_ssl-1:2.2.3-22.el5_3.2.x86_64
list-security done

To list all updates that are security relevant, and get a reutrn code on whether there are security updates use:
# yum --security check-update
To get a list of all BZs that are fixed for packages you have installed use:
# yum list-security bugzillas
To get the information on advisory RHSA-2009:1148-1 use:
# yum info-security RHSA-2009:1148-1
Sample Outputs:

Loaded plugins: rhnplugin, security
===============================================================================
  RHSA-2009:1148
===============================================================================
  Update ID : RHSA-2009:1148-1
    Release :
       Type : security
     Status : final
     Issued : 2009-07-08 23:00:00
       Bugs : 509125 - None
     : 509375 - None
       CVEs : CVE-2009-1890
     : CVE-2009-1891
Description : Important: httpd security update  \The Apache HTTP Server is a
            : popular Web server.  A denial of service flaw was
            : found in the Apache mod_proxy module when it was
            : used as a reverse proxy. A remote attacker could
            : use this flaw to force a proxy process to consume
            : large amounts of CPU time. (CVE-2009-1890)  A
            : denial of service flaw was found in the Apache
            : mod_deflate module. This module continued to
            : compress large files until compression was
            : complete, even if the network connection that
            : requested the content was closed before
            : compression completed. This would cause
            : mod_deflate to consume large amounts of CPU if
            : mod_deflate was enabled for a large file.
            : (CVE-2009-1891)  All httpd users should upgrade to
            : these updated packages, which contain backported
            : patches to correct these issues. After installing
            : the updated packages, the httpd daemon must be
            : restarted for the update to take effect.
      Files : mod_ssl-2.2.3-22.el5_3.2.x86_64.rpm
     : httpd-devel-2.2.3-22.el5_3.2.i386.rpm
     : httpd-2.2.3-22.el5_3.2.x86_64.rpm
     : httpd-devel-2.2.3-22.el5_3.2.x86_64.rpm
     : httpd-manual-2.2.3-22.el5_3.2.x86_64.rpm
     : mod_ssl-2.2.3-22.el5_3.2.i386.rpm
     : httpd-2.2.3-22.el5_3.2.i386.rpm
     : httpd-manual-2.2.3-22.el5_3.2.i386.rpm
info-security done

To get an info list of the latest packages which contain fixes for Bugzilla 3595; CVE # CVE-2009-1890 and advisories RHSA-2009:1148-1, use:
# yum --bz 3595 --cve CVE-2009-1890 --advisory RHSA-2009:1148-1 info updates

How Do I Install All The Security Updates Only?

Type the following command to download and install all the available security updates:
# yum update --security