Kerberos is a networked authentication system that uses a trusted third party (a KDC) to authenticate clients and servers to each other.
Several double-free bugs were found in the Kerberos 5 KDC and libraries. A remote attacker could potentially exploit these flaws to execuate arbitrary code. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the names CAN-2004-0642 and CAN-2004-0643 to these issues.
A double-free bug was also found in the krb524 server (CAN-2004-0772), however this issue was fixed for Red Hat Enterprise Linux 2.1 users by a previous erratum, RHSA-2003:052.
An infinite loop bug was found in the Kerberos 5 ASN.1 decoder library. A remote attacker may be able to trigger this flaw and cause a denial of service. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2004-0644 to this issue.
All users of krb5 should upgrade to these updated packages, which contain backported security patches to resolve these issues.