---
id: CVE-2021-34432
title: >-
  In Eclipse Mosquitto versions 2.0.7 and earlier, the server will crash if the
  client tries to send a PUBLISH packet with topic length = 0.
summary: >-
  In Eclipse Mosquitto versions 2.0.7 and earlier, the server will crash if the
  client tries to send a PUBLISH packet with topic length = 0.
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-20
vendor: eclipse
product: mosquitto
affected:
  - mosquitto <= 2.0.7
published: '2021-07-27'
updated: '2026-07-02'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-34432'
references:
  - url: 'https://bugs.eclipse.org/bugs/show_bug.cgi?id=574141'
    label: emo@eclipse.org
  - url: 'https://bugs.eclipse.org/bugs/show_bug.cgi?id=574141'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01247
epssPercentile: 0.68055
ingestedAt: '2026-07-02T11:33:15.921Z'
---

## Overview

In Eclipse Mosquitto versions 2.0.7 and earlier, the server will crash if the client tries to send a PUBLISH packet with topic length = 0.

## Affected

- `mosquitto <= 2.0.7`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.