A new update is available for Red Hat Enterprise Linux. Here the announcement:
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Red Hat Security Advisory

Synopsis: Moderate: yum-rhn-plugin security update
Advisory ID: RHSA-2008:0815-01
Product: Red Hat Enterprise Linux
Advisory URL: https://rhn.redhat.com/errata/RHSA-2008-0815.html
Issue date: 2008-08-14
CVE Names: CVE-2008-3270
=====================================================================

1. Summary:

Updated yum-rhn-plugin packages that fix a security issue are now available
for Red Hat Enterprise Linux 5.

This update has been rated as having moderate security impact by the Red
Hat Security Response Team.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 5 client) - noarch
Red Hat Enterprise Linux (v. 5 server) - noarch

3. Description:

The yum-rhn-plugin provides support for yum to securely access a Red Hat
Network (RHN) server for software updates.

It was discovered that yum-rhn-plugin did not verify the SSL certificate
for all communication with a Red Hat Network server. An attacker able to
redirect the network communication between a victim and an RHN server could
use this flaw to provide malicious repository metadata. This metadata could
be used to block the victim from receiving specific security updates.
(CVE-2008-3270)

This flaw did not allow an attacker to install malicious packages. Package
signatures were verified and only packages signed with a trusted Red Hat
GPG key were installed.

Red Hat would like to thank Justin Samuel for discussing various package
update mechanism flaws which led to our discovery of this issue.

Users of yum-rhn-plugin are advised to upgrade to this updated packages,
which resolves this issue.

4. Solution:

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/FAQ_58_10188

5. Bugs fixed (http://bugzilla.redhat.com/):

457113 - CVE-2008-3270 yum-rhn-plugin: does not verify SSL certificate for all communication with RHN server

6. Package List:

Red Hat Enterprise Linux Desktop (v. 5 client):

Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Client/en/os/SRPMS/yum-rhn-plugin-0.5.3-12.el5_2.9.src.rpm

noarch:
yum-rhn-plugin-0.5.3-12.el5_2.9.noarch.rpm

Red Hat Enterprise Linux (v. 5 server):

Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Server/en/os/SRPMS/yum-rhn-plugin-0.5.3-12.el5_2.9.src.rpm

noarch:
yum-rhn-plugin-0.5.3-12.el5_2.9.noarch.rpm

These packages are GPG signed by Red Hat for security. Our key and
details on how to verify the signature are available from
https://www.redhat.com/security/team/key/#package

7. References:

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-3270
http://www.redhat.com/security/updates/classification/#moderate

8. Contact:

The Red Hat security contact is . More contact
details at https://www.redhat.com/security/team/contact/

Copyright 2008 Red Hat, Inc.
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