The consume_labels function in avahi-core/dns.c in Avahi before 0.6.16 allows remote attackers to cause a denial of service (infinite loop) via a crafted compressed DNS response with a label that points to itself.
http://www.vupen.com/english/advisories/2007/0071
http://www.ubuntu.com/usn/usn-402-1
http://www.securityfocus.com/bid/21881
http://www.novell.com/linux/security/advisories/2007_007_suse.html
http://www.mandriva.com/security/advisories?name=MDKSA-2007:003
http://www.avahi.org/ticket/84
http://www.avahi.org/changeset/1340
http://www.avahi.org/#December2006
http://secunia.com/advisories/24995
http://secunia.com/advisories/23782
http://secunia.com/advisories/23673
http://secunia.com/advisories/23660
http://secunia.com/advisories/23644
http://secunia.com/advisories/23628