Several security issues were fixed in QEMU.
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)
13 May 2015
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in QEMU.
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)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to restart all QEMU virtual machines to make all the necessary changes.
Vulmon