---
id: CVE-2026-67407
title: RabbitMQ is a messaging and streaming broker
summary: >-
  RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.3.3 and 4.2.9
  and 4.1.14 and 4.0.23, Incomplete fix for CVE-2026-44838: escaperegexchar/1
  does not escape -, leaving room for an MQTT topic permission bypass. the
  CVE-2026-…
severity: medium
cvss: 5.1
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:H/SA:N'
cwe:
  - CWE-862
vendor: rabbitmq
product: rabbitmq-server
affected:
  - 'rabbitmq-server >= 4.3.2, < 4.3.3'
  - 'rabbitmq-server >= 4.2.0, < 4.2.9'
  - 'rabbitmq-server >= 4.1.0, < 4.1.14'
  - 'rabbitmq-server >= 4.0.0, < 4.0.23'
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T18:17:30.073'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67407'
references:
  - url: 'https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9'
    label: security-advisories@github.com
  - url: 'https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3'
    label: security-advisories@github.com
  - url: >-
      https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-q46v-hrvq-hp24
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-25T17:20:18.793859Z'
cvssSource: cna
ingestedAt: '2026-09-25T17:13:14.022Z'
---

## Overview

RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23, Incomplete fix for CVE-2026-44838: escaperegexchar/1 does not escape -, leaving room for an MQTT topic permission bypass. the CVE-2026-44838 fix made expandtopicpermission/2 escape regex metacharacters in expanded topic-permission variables (escaperegex(V)), but escaperegexchar/1 escapes \ ^ $ . | ? + ( ) [ ] { } and omits -. When a topic permission template places {clientid} inside a [...] character class A low-privileged authenticated MQTT user controlling its clientid can broaden topic authorization (read and write) when templates embed {clientid} in a [...] This issue is fixed in versions 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23.

## Remediation

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