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Red Hat Security Advisory
Synopsis: Moderate: kvm security update
Advisory ID: RHSA-2010:0898-01
Product: Red Hat Enterprise Linux
Advisory URL: https://rhn.redhat.com/errata/RHSA-2010-0898.html
Issue date: 2010-12-06
CVE Names: CVE-2010-3698
Updated kvm packages that fix one security issue are now available for Red
Hat Enterprise Linux 5.
The Red Hat Security Response Team has rated this update as having moderate
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.
2. Relevant releases/architectures:
RHEL Desktop Multi OS (v. 5 client) - x86_64
RHEL Virtualization (v. 5 server) - x86_64
KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. KVM is a Linux kernel module built for
the standard Red Hat Enterprise Linux kernel.
A flaw was found in the way QEMU-KVM handled the reloading of fs and gs
segment registers when they had invalid selectors. A privileged host user
with access to "/dev/kvm" could use this flaw to crash the host (denial of
All KVM users should upgrade to these updated packages, which contain a
backported patch to correct this issue. Note: The procedure in the Solution
section must be performed before this update will take effect.
Before applying this update, make sure all previously-released errata
relevant to your system have been applied.
This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
The following procedure must be performed before this update will take
1) Stop all KVM guest virtual machines.
2) Either reboot the hypervisor machine or, as the root user, remove (using
"modprobe -r [module]") and reload (using "modprobe [module]") all of the
following modules which are currently running (determined using "lsmod"):
kvm, ksm, kvm-intel or kvm-amd.
3) Restart the KVM guest virtual machines.
5. Bugs fixed (http://bugzilla.redhat.com/):
639879 - CVE-2010-3698 kvm: invalid selector in fs/gs causes kernel panic
6. Package List:
RHEL Desktop Multi OS (v. 5 client):
RHEL Virtualization (v. 5 server):
These packages are GPG signed by Red Hat for security. Our key and
details on how to verify the signature are available from
The Red Hat security contact is <firstname.lastname@example.org>. More contact
details at https://www.redhat.com/security/team/contact/
Copyright 2010 Red Hat, Inc.
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