avahi-core/socket.c in avahi-daemon in Avahi before 0.6.29 allows remote attackers to cause a denial of service (infinite loop) via an empty mDNS (1) IPv4 or (2) IPv6 UDP packet to port 5353. NOTE: this vulnerability exists because of an incorrect fix for CVE-2010-2244.

Hugo Dias of the Synchron Security Labs discovered a remote denial of service flaw in the avahi daemon. A crafted multicast DNS (mDNS) packet with source port 0 can trigger assertion in originatesfromlocallegacyunicastsocket() function in avahi-core/server.c -- assert(port > 0); -- causing the daemon to call abort() and exit unexpectedly.

Scope of this attack is usually limited to a single LAN.

Ludwig Nussel reported: [1] http://www.openwall.com/lists/oss-security/2010/06/23/4

a deficiency in the way avahi daemon processed packets with corrupted checksum(s). A remote attacker on the same local are network (LAN) could send a DNS packet with broken checksum, that would cause avahi-daemon to exit unexpectedly due to a failed assertion check. Different vulnerability than CVE-2008-5081.