CVE-2021-3468

Name	CVE-2021-3468
Description	A flaw was found in avahi in versions 0.6 up to 0.8. The event used to signal the termination of the client connection on the avahi Unix socket is not correctly handled in the client_work function, allowing a local attacker to trigger an infinite loop. The highest threat from this vulnerability is to the availability of the avahi service, which becomes unresponsive after this flaw is triggered.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-3047-1, DLA-3466-1
Debian Bugs	984938

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
avahi (PTS)	buster	0.7-4+deb10u1	vulnerable
	buster (security)	0.7-4+deb10u3	fixed
	bullseye	0.8-5+deb11u2	fixed
	bookworm	0.8-10	fixed
	sid, trixie	0.8-13	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin	Debian Bugs
avahi	source	stretch	0.6.32-2+deb9u1	DLA-3047-1
avahi	source	buster	0.7-4+deb10u3	DLA-3466-1
avahi	source	bullseye	0.8-5+deb11u2
avahi	source	(unstable)	0.8-7		984938

Notes

https://github.com/lathiat/avahi/pull/330
https://github.com/lathiat/avahi/commit/447affe29991ee99c6b9732fc5f2c1048a611d3b
https://bugzilla.redhat.com/show_bug.cgi?id=1939614#c3