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-2015-2697
  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 oldoldstable distribution (squeeze), these problems have been
fixed in version 1.8.3+dfsg-4squeeze10.

We recommend that you upgrade your krb5 packages.