Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In 0.9-rc2 and earlier, an unprivileged local users can crash avahi-daemon (with wide-area disabled) by creating record browsers with the AVAHI_LOOKUP_USE_WIDE_AREA flag set via D-Bus. This can be done by either calling the RecordBrowserNew method directly or creating hostname/address/service resolvers/browsers that create those browsers internally themselves.
https://github.com/avahi/avahi/security/advisories/GHSA-mhf3-865v-g5rc
https://github.com/avahi/avahi/pull/806
https://github.com/avahi/avahi/commit/ede7048475c5d47d53890e3bc1350dda8e0b3688