(RHSA-2009:0409) Important: krb5 security update

Kerberos is a network authentication system which allows clients and
servers to authenticate to each other using symmetric encryption and a
trusted third party, the Key Distribution Center (KDC).

An input validation flaw was found in the ASN.1 (Abstract Syntax Notation
One) decoder used by MIT Kerberos. A remote attacker could use this flaw to
crash a network service using the MIT Kerberos library, such as kadmind or
krb5kdc, by causing it to dereference or free an uninitialized pointer.
(CVE-2009-0846)

All krb5 users should upgrade to these updated packages, which contain a
backported patch to correct this issue. All running services using the MIT
Kerberos libraries must be restarted for the update to take effect.