Certain weaknesses in the implementation of version 4 of the Kerberos protocol (krb4) in the krb5 distribution, when triple-DES keys are used to key krb4 services, allow an attacker to create krb4 tickets for unauthorized principals using a cut-and-paste attack and "ticket splicing."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A250
http://www.securityfocus.com/archive/1/317130/30/25250/threaded
http://www.securityfocus.com/archive/1/316960/30/25250/threaded
http://www.redhat.com/support/errata/RHSA-2003-091.html
http://www.redhat.com/support/errata/RHSA-2003-052.html
http://www.redhat.com/support/errata/RHSA-2003-051.html
http://www.kb.cert.org/vuls/id/442569
http://www.debian.org/security/2003/dsa-273
http://www.debian.org/security/2003/dsa-266
http://web.mit.edu/kerberos/www/advisories/MITKRB5-SA-2003-004-krb4.txt