C secunia:

Emanuele Aina has reported a security issue in Avahi, which can be exploited by
malicious, local users to cause a DoS (Denial of Service).

The security issue is caused due to an "assert()" error when receiving empty TXT
data over D-Bus for registration. This can be exploited to terminate the Avahi
daemon by sending empty TXT data.

Ну и два репецта.
1) обновится до 0.6.20
2) или http://avahi.org/changeset/1482

p.s.: почему-то http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3372
говорит что такого CVE нет, хотя на secunia указано именно так.