linux - security update

Several vulnerabilities have been discovered in the Linux kernel that
may lead to a denial of service.

• CVE-2015-5307
  Ben Serebrin from Google discovered a guest to host denial of
  service flaw affecting the KVM hypervisor. A malicious guest can
  trigger an infinite stream of alignment check (#AC) exceptions
  causing the processor microcode to enter an infinite loop where the
  core never receives another interrupt. This leads to a panic of the
  host kernel.
• CVE-2015-7833
  Sergej Schumilo, Hendrik Schwartke and Ralf Spenneberg discovered a
  flaw in the processing of certain USB device descriptors in the
  usbvision driver. An attacker with physical access to the system can
  use this flaw to crash the system.
• CVE-2015-7872
  Dmitry Vyukov discovered a vulnerability in the keyrings garbage
  collector allowing a local user to trigger a kernel panic.
• CVE-2015-7990
  It was discovered that the fix for CVE-2015-6937 was incomplete. A
  race condition when sending a message on unbound socket can still
  cause a NULL pointer dereference. A remote attacker might be able to
  cause a denial of service (crash) by sending a crafted packet.

For the oldstable distribution (wheezy), these problems have been fixed
in version 3.2.68-1+deb7u6.

For the stable distribution (jessie), these problems have been fixed in
version 3.16.7-ckt11-1+deb8u6.

We recommend that you upgrade your linux packages.