CVE-2021-20237

An uncontrolled resource consumption (memory leak) flaw was found in ZeroMQ's src/xpub.cpp in versions before 4.3.3. This flaw allows a remote unauthenticated attacker to send crafted PUB messages that consume excessive memory if the CURVE/ZAP authentication is disabled on the server, causing a denial of service. The highest threat from this vulnerability is to system availability.

• CWE-400
• CWE-401

• https://bugzilla.redhat.com/show_bug.cgi?id=1921989Issue Tracking, Third Party Advisory
• https://github.com/zeromq/libzmq/security/advisories/GHSA-4p5v-h92w-6wxwPatch, Third Party Advisory
• https://bugzilla.redhat.com/show_bug.cgi?id=1921989Issue Tracking, Third Party Advisory
• https://github.com/zeromq/libzmq/security/advisories/GHSA-4p5v-h92w-6wxwPatch, Third Party Advisory

Published

May 28, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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