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 . A NULL pointer dereference flaw was found in the way the MIT Kerberos KDC processed principal names that were not null terminated, when the KDC was configured to use an LDAP back end. A remote attacker could use this flaw to crash the KDC via a specially-crafted request. A denial of service flaw was found in the way the MIT Kerberos KDC processed certain principal names when the KDC was configured to use an LDAP back end. A remote attacker could use this flaw to cause the KDC to hang via a specially-crafted request. Red Hat would like to thank the MIT Kerberos Team for reporting these issues. Upstream acknowledges Kevin Longfellow of Oracle Corporation as the original reporter of the CVE-2011-0281 issue. All krb5 users should upgrade to these updated packages, which contain a backported patch to correct these issues. After installing the updated packages, the krb5kdc daemon will be restarted automatically.