QEMU could be made to crash or run programs.
It was discovered that QEMU incorrectly handled certain VT100 escape sequences. A guest user with access to an emulated character device could use this flaw to cause QEMU to crash, or possibly execute arbitrary code on the host.
2 October 2012
A security issue affects these releases of Ubuntu and its derivatives:
QEMU could be made to crash or run programs.
It was discovered that QEMU incorrectly handled certain VT100 escape sequences. A guest user with access to an emulated character device could use this flaw to cause QEMU to crash, or possibly execute arbitrary code on the host.
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 your virtual machines to make all the necessary changes.