The check_rpcsec_auth function in kadmin/server/kadm_rpc_svc.c in kadmind in MIT Kerberos 5 (aka krb5) through 1.11.5, 1.12.x through 1.12.2, and 1.13.x before 1.13.1 allows remote authenticated users to bypass a kadmin/* authorization check and obtain administrative access by leveraging access to a two-component principal with an initial "kadmind" substring, as demonstrated by a "ka/x" principal.
https://github.com/krb5/krb5/commit/6609658db0799053fbef0d7d0aa2f1fd68ef32d8
http://www.ubuntu.com/usn/USN-2498-1
http://www.securityfocus.com/bid/72494
http://www.mandriva.com/security/advisories?name=MDVSA-2015:069
http://www.debian.org/security/2015/dsa-3153
http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2015-001.txt
http://web.mit.edu/kerberos/advisories/2015-001-patch-r113.txt
http://rhn.redhat.com/errata/RHSA-2015-0794.html
http://rhn.redhat.com/errata/RHSA-2015-0439.html
http://lists.opensuse.org/opensuse-updates/2015-02/msg00044.html
http://lists.opensuse.org/opensuse-security-announce/2015-02/msg00016.html
http://lists.opensuse.org/opensuse-security-announce/2015-02/msg00011.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-March/151437.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-March/151103.html