The vmware-vga driver (hw/display/vmware_vga.c) in QEMU allows local guest users to write to qemu memory locations and gain privileges via unspecified parameters related to rectangle handling.
https://www.mail-archive.com/qemu-devel%40nongnu.org/msg261580.html
http://www.ubuntu.com/usn/USN-2409-1
http://www.debian.org/security/2014/dsa-3067
http://www.debian.org/security/2014/dsa-3066
http://secunia.com/advisories/62144