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.

Attack Vector Network

Attack Complexity Low

Privileges Required High

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00353.

Exploitation poc

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
rabbitmq rabbitmq-server affected
Version Status Constraints
>= 4.0.0, < 4.0.22 affected —
>= 4.1.0, < 4.1.14 affected —
>= 4.2.0, < 4.2.7 affected —

No data.

No data.

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Vendors Products
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Rabbitmq-server Subscribe

Project Subscriptions

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Rabbitmq Subscribe
Rabbitmq-server Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/rabbitmq/rabbitmq-server/commit/86601c5a6d1c7e41060e3dbd165c88bdc91266ee cve-icon cve-icon
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7 cve-icon cve-icon
https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-34c7-r8w9-5wv8 cve-icon cve-icon cve-icon
History

Sat, 26 Sep 2026 11:30:00 +0000

Type Values Removed Values Added
First Time appeared Rabbitmq
Rabbitmq rabbitmq-server
Vendors & Products Rabbitmq
Rabbitmq rabbitmq-server

Fri, 25 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 25 Sep 2026 16:45:00 +0000

Type Values Removed Values Added
Description 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.
Title RabbitMQ: Admin-only atom exhaustion: PUT /api/users tags list
Weaknesses CWE-400
References
Metrics cvssV4_0

{'score': 6.9, 'vector': '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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-25T19:55:13.807Z

Reserved: 2026-07-28T19:50:39.437Z

Link: CVE-2026-67226

cve-icon Vulnrichment

Updated: 2026-09-25T19:54:50.562Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-25T17:17:11.000

Modified: 2026-09-28T14:38:38.163

Link: CVE-2026-67226

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-26T11:15:10Z

Weaknesses