CVE-2021-20236

Name	CVE-2021-20236
Description	A flaw was found in the ZeroMQ server in versions before 4.3.3. This flaw allows a malicious client to cause a stack buffer overflow on the server by sending crafted topic subscription requests and then unsubscribing. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
zeromq3 (PTS)	bookworm	4.3.4-6	fixed
	forky, sid, trixie	4.3.5-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
zeromq3	source	(unstable)	4.3.3-1

Notes

[buster] - zeromq3 <no-dsa> (Minor issue)
[stretch] - zeromq3 <ignored> (Minor issue, too intrusive to backport)
https://github.com/zeromq/libzmq/pull/3959
https://github.com/zeromq/libzmq/security/advisories/GHSA-qq65-x72m-9wr8
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=22488