Important: krb5 security update

Updated krb5 packages that fix two security flaws are now available for
Red Hat Enterprise Linux 5.

This update has been rated as having important security impact by the Red
Hat Security Response Team.

Kerberos is a network authentication system which allows clients and
servers to authenticate to each other through use of symmetric encryption
and a trusted third party, the KDC. kadmind is the KADM5 administration
server.

Tenable Network Security discovered a stack buffer overflow flaw in the RPC
library used by kadmind. A remote unauthenticated attacker who can access
kadmind could trigger this flaw and cause kadmind to crash. On Red Hat
Enterprise Linux 5 it is not possible to exploit this flaw to run arbitrary
code as the overflow is blocked by FORTIFY_SOURCE. (CVE-2007-3999)

Garrett Wollman discovered an uninitialized pointer flaw in kadmind. A
remote unauthenticated attacker who can access kadmind could trigger this
flaw and cause kadmind to crash. (CVE-2007-4000)

These issues did not affect the versions of Kerberos distributed with Red
Hat Enterprise Linux 2.1, 3, or 4.

Users of krb5-server are advised to update to these erratum packages which
contain backported fixes to correct these issues.

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/FAQ_58_10188

250973 - CVE-2007-3999 krb5 RPC library buffer overflow
250976 - CVE-2007-4000 krb5 kadmind uninitialized pointer

https://www.redhat.com/security/data/cve/CVE-2007-3999.html
https://www.redhat.com/security/data/cve/CVE-2007-4000.html
http://www.redhat.com/security/updates/classification/#important