---
id: CVE-2026-67226
title: RabbitMQ is a messaging and streaming broker
summary: >-
  RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.0.22 and
  4.1.14 and 4.2.7, Admin-only atom exhaustion: PUT /api/users tags list.
  settags/2 maps rabbitdatacoercion:toatom/1 over the user's tags list. The 20
  MB management …
severity: medium
cvss: 6.9
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-400
  - CWE-770
vendor: rabbitmq
product: rabbitmq-server
affected:
  - 'rabbitmq-server >= 4.0.0, < 4.0.22'
  - 'rabbitmq-server >= 4.1.0, < 4.1.14'
  - 'rabbitmq-server >= 4.2.0, < 4.2.7'
published: '2026-09-25'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T14:38:38.163'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67226'
references:
  - url: >-
      https://github.com/rabbitmq/rabbitmq-server/commit/86601c5a6d1c7e41060e3dbd165c88bdc91266ee
    label: security-advisories@github.com
  - url: 'https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7'
    label: security-advisories@github.com
  - url: >-
      https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-34c7-r8w9-5wv8
    label: security-advisories@github.com
  - url: >-
      https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-34c7-r8w9-5wv8
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-67226.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-67226'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541518'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-67226'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67226'
  - url: 'https://access.redhat.com/errata/RHSA-2026:67552'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00389
epssPercentile: 0.32869
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-25T19:55:06.667719Z'
cvssSource: cna
ingestedAt: '2026-09-25T17:13:14.022Z'
patched:
  - hardened_images
scores:
  cna: 6.9
  vendor: 4.9
---

## Overview

RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.0.22 and 4.1.14 and 4.2.7, Admin-only atom exhaustion: PUT /api/users tags list. settags/2 maps rabbitdatacoercion:toatom/1 over the user's tags list. The 20 MB management body limit fits ~3-4M short tag strings. An administrator can crash the node in a single request by creating a user (or importing definitions) with ~1M unique tag administrator. This issue is fixed in versions 4.0.22 and 4.1.14 and 4.2.7.

## Remediation

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

## Vendor advisories

- **RHSA-2026:67552** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67552)
- **Red Hat VEX** · Moderate · affected: Red Hat Hardened Images, Red Hat OpenStack Platform 13 (Queens), Red Hat OpenStack Platform 16.2, Red Hat OpenStack Platform 17.1, Red Hat OpenStack Platform 18.0 · no fix planned: Red Hat OpenStack Platform 13 (Queens), Red Hat OpenStack Platform 16.2, Red Hat OpenStack Platform 17.1, Red Hat Hardened Images, … · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-67226.json)