xen - security update

Multiple security issues have been discovered in the Xen virtualisation
solution which may result in denial of service, information disclosure
or privilege escalation.

• CVE-2014-8594
  Roger Pau Monne and Jan Beulich discovered that incomplete
  restrictions on MMU update hypercalls may result in privilege
  escalation.
• CVE-2014-8595
  Jan Beulich discovered that missing privilege level checks in the
  x86 emulation of far branches may result in privilege escalation.
• CVE-2014-8866
  Jan Beulich discovered that an error in compatibility mode hypercall
  argument translation may result in denial of service.
• CVE-2014-8867
  Jan Beulich discovered that an insufficient restriction in
  acceleration support for the REP MOVS instruction may result in
  denial of service.
• CVE-2014-9030
  Andrew Cooper discovered a page reference leak in MMU_MACHPHYS_UPDATE
  handling, resulting in denial of service.

For the stable distribution (wheezy), these problems have been fixed in
version 4.1.4-3+deb7u4.

For the upcoming stable distribution (jessie), these problems have been
fixed in version 4.4.1-4.

For the unstable distribution (sid), these problems have been fixed in
version 4.4.1-4.

We recommend that you upgrade your xen packages.