CVE-2021-20236

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.

• CWE-120
• CWE-787

• https://bugzilla.redhat.com/show_bug.cgi?id=1921976Issue Tracking, Third Party Advisory
• https://github.com/zeromq/libzmq/security/advisories/GHSA-qq65-x72m-9wr8Patch, Third Party Advisory
• https://bugzilla.redhat.com/show_bug.cgi?id=1921976Issue Tracking, Third Party Advisory
• https://github.com/zeromq/libzmq/security/advisories/GHSA-qq65-x72m-9wr8Patch, 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.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
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