USN-2608-1: QEMU vulnerabilities

13 May 2015

qemu, qemu-kvm vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 15.04
  • Ubuntu 14.10
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS


Several security issues were fixed in QEMU.

Software Description

  • qemu - Machine emulator and virtualizer
  • qemu-kvm - Machine emulator and virtualizer


Jason Geffner discovered that QEMU incorrectly handled the virtual floppy driver. This issue is known as VENOM. A malicious guest could use this issue to cause a denial of service, or possibly execute arbitrary code on the host as the user running the QEMU process. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. (CVE-2015-3456)

Daniel P. Berrange discovered that QEMU incorrectly handled VNC websockets. A remote attacker could use this issue to cause QEMU to consume memory, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 14.10 and Ubuntu 15.04. (CVE-2015-1779)

Jan Beulich discovered that QEMU, when used with Xen, didn’t properly restrict access to PCI command registers. A malicious guest could use this issue to cause a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 14.10. (CVE-2015-2756)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 15.04
qemu-system - 1:2.2+dfsg-5expubuntu9.1
qemu-system-aarch64 - 1:2.2+dfsg-5expubuntu9.1
qemu-system-arm - 1:2.2+dfsg-5expubuntu9.1
qemu-system-mips - 1:2.2+dfsg-5expubuntu9.1
qemu-system-misc - 1:2.2+dfsg-5expubuntu9.1
qemu-system-ppc - 1:2.2+dfsg-5expubuntu9.1
qemu-system-sparc - 1:2.2+dfsg-5expubuntu9.1
qemu-system-x86 - 1:2.2+dfsg-5expubuntu9.1
Ubuntu 14.10
qemu-system - 2.1+dfsg-4ubuntu6.6
qemu-system-aarch64 - 2.1+dfsg-4ubuntu6.6
qemu-system-arm - 2.1+dfsg-4ubuntu6.6
qemu-system-mips - 2.1+dfsg-4ubuntu6.6
qemu-system-misc - 2.1+dfsg-4ubuntu6.6
qemu-system-ppc - 2.1+dfsg-4ubuntu6.6
qemu-system-sparc - 2.1+dfsg-4ubuntu6.6
qemu-system-x86 - 2.1+dfsg-4ubuntu6.6
Ubuntu 14.04 LTS
qemu-system - 2.0.0+dfsg-2ubuntu1.11
qemu-system-aarch64 - 2.0.0+dfsg-2ubuntu1.11
qemu-system-arm - 2.0.0+dfsg-2ubuntu1.11
qemu-system-mips - 2.0.0+dfsg-2ubuntu1.11
qemu-system-misc - 2.0.0+dfsg-2ubuntu1.11
qemu-system-ppc - 2.0.0+dfsg-2ubuntu1.11
qemu-system-sparc - 2.0.0+dfsg-2ubuntu1.11
qemu-system-x86 - 2.0.0+dfsg-2ubuntu1.11
Ubuntu 12.04 LTS
qemu-kvm - 1.0+noroms-0ubuntu14.22

To update your system, please follow these instructions:

After a standard system update you need to restart all QEMU virtual machines to make all the necessary changes.