---
id: CVE-2026-67222
title: RabbitMQ is a messaging and streaming broker
summary: >-
  RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.15,
  4.0.20, 4.1.11, and 4.2.6, mechanisms/1 applied list_to_atom/1 to every
  colon-delimited token in an attacker-controlled auth_mechanism value,
  permanently consuming …
severity: medium
cvss: 5.9
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-400
vendor: rabbitmq
product: rabbitmq-server
affected:
  - 'rabbitmq-server >= 3.13.0, < 3.13.15'
  - 'rabbitmq-server >= 4.0.0, < 4.0.20'
  - 'rabbitmq-server >= 4.1.0, < 4.1.11'
  - 'rabbitmq-server >= 4.2.0, < 4.2.6'
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T17:17:10.517'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67222'
references:
  - url: 'https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6'
    label: security-advisories@github.com
  - url: >-
      https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-85jr-6rr2-j73r
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
cvssSource: cna
ingestedAt: '2026-09-25T17:13:14.031Z'
---

## Overview

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.15, 4.0.20, 4.1.11, and 4.2.6, mechanisms/1 applied list_to_atom/1 to every colon-delimited token in an attacker-controlled auth_mechanism value, permanently consuming Erlang VM atoms and allowing the node to be crashed with a large request. Exploitation requires the Shovel or Federation plugin to be in use, and setting auth_mechanism requires the policymaker tag. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6.

## Remediation

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