Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In versions 0.9rc2 and below, avahi-daemon can be crashed via a segmentation fault by sending an unsolicited mDNS response containing a recursive CNAME record, where the alias and canonical name point to the same domain (e.g., "h.local" as a CNAME for "h.local"). This causes unbounded recursion in the lookup_handle_cname function, leading to stack exhaustion. The vulnerability affects record browsers where AVAHI_LOOKUP_USE_MULTICAST is set explicitly, which includes record browsers created by resolvers used by nss-mdns. This issue is patched in commit 78eab31128479f06e30beb8c1cbf99dd921e2524.

A flaw was found in the Avahi-daemon, where it initializes DNS transaction IDs randomly only once at startup, incrementing them sequentially after that. This predictable behavior facilitates DNS spoofing attacks, allowing attackers to guess transaction IDs.

A flaw was found in Avahi-daemon, which relies on fixed source ports for wide-area DNS queries. This issue simplifies attacks where malicious DNS responses are injected.

A vulnerability was found in Avahi. A reachable assertion exists in the dbus_set_host_name function.

A vulnerability was found in Avahi. A reachable assertion exists in the avahi_rdata_parse() function.

A vulnerability was found in Avahi. A reachable assertion exists in the avahi_alternative_host_name() function.

A vulnerability was found in Avahi. A reachable assertion exists in the avahi_escape_label() function.

A vulnerability was found in Avahi, where a reachable assertion exists in avahi_dns_packet_append_record.