Red Hat has issued a security update for its Kernel that fixes issues related to following packages. This update has been rated as having important security impact on RHEL 4.x / 5.x, and you are recommended to update system as soon as possible.

=> Updated GFS-kernel, gnbd-kernel,dlm-kernel, cmirror-kernel, cman-kernel, Virtualization_Guide, Cluster_Administration, and lobal_File_System packages that fix module loading and others issues under RHEL 4.x and 5.x available now.

How do I update my system?

Simply type the following two commands:
# yum update
Sample output:

Loading "rhnplugin" plugin
Loading "security" plugin

rhel-x86_64-server-vt-5   100% |=========================| 1.2 kB    00:00
rhel-x86_64-server-5      100% |=========================| 1.2 kB    00:00
Skipping security plugin, no data
Setting up Update Process
Resolving Dependencies
Skipping security plugin, no data
--> Running transaction check
---> Package kernel.x86_64 0:2.6.18-92.1.6.el5 set to be installed
---> Package kernel-devel.x86_64 0:2.6.18-92.1.6.el5 set to be installed
---> Package kernel-headers.x86_64 0:2.6.18-92.1.6.el5 set to be updated
---> Package Deployment_Guide-en-US.noarch 0:5.2-11 set to be updated
--> Finished Dependency Resolution
--> Running transaction check
---> Package kernel.x86_64 0:2.6.18-53.1.21.el5 set to be erased
---> Package kernel.x86_64 0:2.6.18-92.1.6.el5 set to be installed
---> Package kernel-devel.x86_64 0:2.6.18-92.1.6.el5 set to be installed
---> Package kernel-headers.x86_64 0:2.6.18-92.1.6.el5 set to be updated
---> Package Deployment_Guide-en-US.noarch 0:5.2-11 set to be updated
---> Package kernel-devel.x86_64 0:2.6.18-53.1.21.el5 set to be erased
--> Finished Dependency Resolution

Dependencies Resolved

=============================================================================
 Package                 Arch       Version          Repository        Size
=============================================================================
Installing:
 kernel                  x86_64     2.6.18-92.1.6.el5  rhel-x86_64-server-5   16 M
 kernel-devel            x86_64     2.6.18-92.1.6.el5  rhel-x86_64-server-5  5.0 M
Updating:
 Deployment_Guide-en-US  noarch     5.2-11           rhel-x86_64-server-5  3.5 M
 kernel-headers          x86_64     2.6.18-92.1.6.el5  rhel-x86_64-server-5  880 k
Removing:
 kernel                  x86_64     2.6.18-53.1.21.el5  installed          75 M
 kernel-devel            x86_64     2.6.18-53.1.21.el5  installed          15 M

Transaction Summary
=============================================================================
Install      2 Package(s)
Update       2 Package(s)
Remove       2 Package(s)

Total download size: 25 M
Is this ok [y/N]: y