qemu - security update

Several vulnerabilities were discovered in qemu, a fast processor
emulator.

• CVE-2016-3710
  Wei Xiao and Qinghao Tang of 360.cn Inc discovered an out-of-bounds
  read and write flaw in the QEMU VGA module. A privileged guest user
  could use this flaw to execute arbitrary code on the host with the
  privileges of the hosting QEMU process.
• CVE-2016-3712
  Zuozhi Fzz of Alibaba Inc discovered potential integer overflow
  or out-of-bounds read access issues in the QEMU VGA module. A
  privileged guest user could use this flaw to mount a denial of
  service (QEMU process crash).

For the stable distribution (jessie), these problems have been fixed in
version 1:2.1+dfsg-12+deb8u6.

We recommend that you upgrade your qemu packages.