CVE-2021-34432

Name: CVE-2021-34432
Creator: NVD / NIST
Published: 2021-07-27T16:15:07.893+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.25%

Last modified Jun 17, 2026

CVE-2021-34432 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. In Eclipse Mosquitto versions 2.07 and earlier, the server will crash if the client tries to send a PUBLISH packet with topic length = 0.. EPSS estimates a 1.25% chance of exploitation in the next 30 days.

Description

In Eclipse Mosquitto versions 2.07 and earlier, the server will crash if the client tries to send a PUBLISH packet with topic length = 0.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.25%

65.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-20

Affected Software

Vendor	Product	Versions
Eclipse	Mosquitto	<= 2.0.7

References

https://bugs.eclipse.org/bugs/show_bug.cgi?id=574141Exploit, Issue Tracking, Patch, Vendor Advisory
https://bugs.eclipse.org/bugs/show_bug.cgi?id=574141Exploit, Issue Tracking, Patch, Vendor Advisory

Timeline

Published: Jul 27, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-34432?

In Eclipse Mosquitto versions 2.07 and earlier, the server will crash if the client tries to send a PUBLISH packet with topic length = 0.

How severe is CVE-2021-34432?

CVE-2021-34432 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.25% probability of exploitation in the next 30 days.

How do I fix CVE-2021-34432?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-34432?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST