Updated krb5 packages that fix multiple security issues are now available for Red Hat Enterprise Linux 6. The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section. Description 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 . Multiple NULL pointer dereference and assertion failure flaws were found in the MIT Kerberos KDC when it was configured to use an LDAP or Berkeley Database back end. A remote attacker could use these flaws to crash the KDC. Red Hat would like to thank the MIT Kerberos project for reporting the CVE-2011-1527 issue. Upstream acknowledges Andrej Ota as the original reporter of CVE-2011-1527. 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.