Kerberos is a network authentication system which allows clients andservers to authenticate to each other using symmetric encryption and atrusted third party, the Key Distribution Center (KDC).A NULL pointer dereference flaw was discovered in the MIT Kerberos GenericSecurity Service Application Program Interface (GSS-API) library. A remote,authenticated attacker could use this flaw to crash any server applicationusing the GSS-API authentication mechanism, by sending a specially-craftedGSS-API token with a missing checksum field. (CVE-2010-1321)Red Hat would like to thank the MIT Kerberos Team for responsibly reportingthis issue. Upstream acknowledges Shawn Emery of Oracle as the originalreporter.All krb5 users should upgrade to these updated packages, which contain abackported patch to correct this issue. All running services using the MITKerberos libraries must be restarted for the update to take effect.