Several security issues were fixed in QEMU.
Cyrille Chatras discovered that QEMU incorrectly handled certain PS2 values during migration. An attacker could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 18.04 LTS. (CVE-2017-16845)
16 May 2018
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in QEMU.
Cyrille Chatras discovered that QEMU incorrectly handled certain PS2 values during migration. An attacker could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 18.04 LTS. (CVE-2017-16845)
Cyrille Chatras discovered that QEMU incorrectly handled multiboot. An attacker could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code on the host. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. (CVE-2018-7550)
Ross Lagerwall discovered that QEMU incorrectly handled the Cirrus VGA device. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 17.10 and Ubuntu 18.04 LTS. (CVE-2018-7858)
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.