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).
Multiple NULL pointer dereference and assertion failure flaws were found in the MIT Kerberos KDC when it was configured to use an LDAP (Lightweight Directory Access Protocol) or Berkeley Database (Berkeley DB) back end. A remote attacker could use these flaws to crash the KDC. (CVE-2011-1527, CVE-2011-1528, CVE-2011-1529)
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.