PowerDNS before 2.9.21.2 allows remote attackers to cause a denial of service (daemon crash) via a CH HINFO query.
http://lists.opensuse.org/opensuse-security-announce/2008-12/msg00002.html
http://secunia.com/advisories/32979
http://secunia.com/advisories/33264
http://security.gentoo.org/glsa/glsa-200812-19.xml