krb5 - security update

Several vulnerabilities were discovered in krb5, the MIT implementation
of Kerberos. The Common Vulnerabilities and Exposures project identifies
the following problems:

• CVE-2015-2695
  It was discovered that applications which call gss_inquire_context()
  on a partially-established SPNEGO context can cause the GSS-API
  library to read from a pointer using the wrong type, leading to a
  process crash.
• CVE-2015-2696
  It was discovered that applications which call gss_inquire_context()
  on a partially-established IAKERB context can cause the GSS-API
  library to read from a pointer using the wrong type, leading to a
  process crash.
• CVE-2015-2697
  It was discovered that the build_principal_va() function incorrectly
  handles input strings. An authenticated attacker can take advantage
  of this flaw to cause a KDC to crash using a TGS request with a
  large realm field beginning with a null byte.

For the oldstable distribution (wheezy), these problems have been fixed
in version 1.10.1+dfsg-5+deb7u4.

For the stable distribution (jessie), these problems have been fixed in
version 1.12.1+dfsg-19+deb8u1.

For the testing distribution (stretch), these problems have been fixed
in version 1.13.2+dfsg-3.

For the unstable distribution (sid), these problems have been fixed in
version 1.13.2+dfsg-3.

We recommend that you upgrade your krb5 packages.