CentOS security update check

[root@localhost tmp]# cat /etc/redhat-release
CentOS release 5.5 (Final)

[root@localhost tmp]# uname -a
Linux localhost.localdomain 2.6.18-238.12.1.el5xen #1 SMP Tue May 31 14:02:29 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux

So the system is half-updated from 5.5 to 5.7.

[root@localhost bin]# ./check_yum
YUM OK: 0 Security Updates Available. 138 Non-Security Updates Available
[root@localhost tmp]# yum --security check-update                               Loaded plugins: downloadonly, fastestmirror, security
Loading mirror speeds from cached hostfile
 * base: centos.psw.net
 * epel: ftp.uni-koeln.de
 * extras: centos.psw.net
 * updates: centos.psw.net
Centos-5.5-x86_64-UPDATES                                |  951 B     00:00
Centos-5.6-x86_64-UPDATES                                |  951 B     00:00
addons                                                   |  951 B     00:00
base                                                     | 1.1 kB     00:00
core-0                                                   | 1.1 kB     00:00
epel                                                     | 3.7 kB     00:00
extras                                                   | 2.1 kB     00:00
updates                                                  | 1.9 kB     00:00
Limiting package lists to security relevant ones
No packages needed, for security, 138 available
[root@localhost tmp]# /usr/lib64/nagios/plugins/check_updates -t 30 -w 20 -c 50
CHECK_UPDATES WARNING - 138 non-critical updates available | total_updates=138;20;50 security_updates=0;20;50
SysVinit.x86_64
amtu.x86_64
audit.x86_64
audit-libs.i386
audit-libs.x86_64
audit-libs-python.x86_64
authconfig.x86_64
bash.x86_64
bind-libs.x86_64
bind-utils.x86_64
centos-release.x86_64
centos-release-notes.x86_64
coolkey.i386
coolkey.x86_64
coreutils.x86_64
cpuspeed.x86_64
crash.x86_64
cryptsetup-luks.i386
cryptsetup-luks.x86_64
curl.x86_64
dbus.x86_64
dbus-libs.x86_64
device-mapper.i386
device-mapper.x86_64
device-mapper-event.x86_64
device-mapper-multipath.x86_64
dhclient.x86_64
dhcpv6-client.x86_64
dmidecode.x86_64
dmraid.x86_64
dmraid-events.x86_64
dump.x86_64
e2fsprogs.x86_64
e2fsprogs-libs.i386
e2fsprogs-libs.x86_64
ecryptfs-utils.i386
ecryptfs-utils.x86_64
finger.x86_64
gettext.x86_64
glibc.i686
glibc.x86_64
glibc-common.x86_64
gzip.x86_64
hal.x86_64
hwdata.noarch
initscripts.x86_64
iscsi-initiator-utils.x86_64
kernel-xen.x86_64
kpartx.x86_64
krb5-libs.i386
krb5-libs.x86_64
krb5-workstation.x86_64
ksh.x86_64
less.x86_64
libgcc.i386
libgcc.x86_64
libhugetlbfs.i386
libhugetlbfs.x86_64
libpng.i386
libpng.x86_64
libselinux.i386
libselinux.x86_64
libselinux-python.x86_64
libselinux-utils.x86_64
libstdc++.i386
libstdc++.x86_64
libsysfs.x86_64
libvolume_id.x86_64
libxml2.x86_64
libxml2-python.x86_64
logrotate.x86_64
lvm2.x86_64
m2crypto.x86_64
man.x86_64
man-pages.noarch
microcode_ctl.x86_64
mkinitrd.i386
mkinitrd.x86_64
nash.x86_64
nscd.x86_64
nspr.i386
nspr.x86_64
nss.i386
nss.x86_64
nss-tools.x86_64
nss_ldap.i386
nss_ldap.x86_64
oddjob.x86_64
oddjob-libs.x86_64
openldap.i386
openldap.x86_64
openssh.x86_64
openssh-clients.x86_64
openssh-server.x86_64
openssl.i686
openssl.x86_64
pam_krb5.i386
pam_krb5.x86_64
pango.i386
pango.x86_64
parted.i386
parted.x86_64
passwd.x86_64
patch.x86_64
pciutils.x86_64
perl.x86_64
popt.x86_64
procps.x86_64
python.x86_64
python-libs.x86_64
python-urlgrabber.noarch
redhat-lsb.i386
redhat-lsb.x86_64
rmt.x86_64
rng-utils.x86_64
rpm.x86_64
rpm-libs.x86_64
rpm-python.x86_64
rsync.x86_64
selinux-policy.noarch
selinux-policy-targeted.noarch
sendmail.x86_64
sos.noarch
sudo.x86_64
sysfsutils.x86_64
system-config-network-tui.noarch
system-config-securitylevel-tui.x86_64
talk.x86_64
tmpwatch.x86_64
traceroute.x86_64
tzdata.x86_64
udev.x86_64
util-linux.x86_64
vim-minimal.x86_64
yum.noarch
yum-fastestmirror.noarch
zlib.i386
zlib.x86_64