The setup_server_realm function in main.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.10.7, when multiple realms are configured, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted request.
https://lists.debian.org/debian-lts-announce/2018/01/msg00040.html
https://github.com/krb5/krb5/commit/c2ccf4197f697c4ff143b8a786acdd875e70a89d
https://bugzilla.redhat.com/show_bug.cgi?id=1026942
http://www.securityfocus.com/bid/63555
http://web.mit.edu/kerberos/krb5-1.11/README-1.11.4.txt
http://web.mit.edu/kerberos/krb5-1.10/README-1.10.7.txt
http://lists.opensuse.org/opensuse-updates/2013-12/msg00026.html
http://lists.opensuse.org/opensuse-updates/2013-11/msg00086.html
http://lists.opensuse.org/opensuse-updates/2013-11/msg00082.html