Rapid7 Vulnerability & Exploit Database

RHSA-2012:0050: qemu-kvm security, bug fix, and enhancement update

Back to Search

RHSA-2012:0050: qemu-kvm security, bug fix, and enhancement update



KVM (Kernel-based Virtual Machine) is a full virtualization solution forLinux on AMD64 and Intel 64 systems. qemu-kvm is the user-space componentfor running virtual machines using KVM.A heap overflow flaw was found in the way QEMU-KVM emulated the e1000network interface card. A privileged guest user in a virtual machine whosenetwork interface is configured to use the e1000 emulated driver could usethis flaw to crash the host or, possibly, escalate their privileges on thehost. (CVE-2012-0029)Red Hat would like to thank Nicolae Mogoreanu for reporting this issue.This update also fixes the following bug:This mitigation is only required if you do not have the RHSA-2011:1849kernel update installed on the host and you are using raw format virtiodisks backed by a partition or LVM volume.If you run guests by invoking /usr/libexec/qemu-kvm directly, use the"-global virtio-blk-pci.scsi=off" option to apply the mitigation. If youare using libvirt, as recommended by Red Hat, and have the RHBA-2012:0013libvirt update installed, no manual action is required: guests willautomatically use "scsi=off". (BZ#767721)Note: After installing the RHSA-2011:1849 kernel update, SCSI requestsissued by guests via the SG_IO IOCTL will not be passed to the underlyingblock device when using raw format virtio disks backed by a partition orLVM volume, even if "scsi=on" is used.As well, this update adds the following enhancement:All users of qemu-kvm should upgrade to these updated packages, whichcorrect these issues and add this enhancement. After installing thisupdate, shut down all running virtual machines. Once all virtual machineshave shut down, start them again for this update to take effect.


  • redhat-upgrade-qemu-img
  • redhat-upgrade-qemu-kvm
  • redhat-upgrade-qemu-kvm-debuginfo
  • redhat-upgrade-qemu-kvm-tools

With Rapid7 live dashboards, I have a clear view of all the assets on my network, which ones can be exploited, and what I need to do in order to reduce the risk in my environment in real-time. No other tool gives us that kind of value and insight.

– Scott Cheney, Manager of Information Security, Sierra View Medical Center