Medium 6.9Published Sep 25, 2026

CVE-2026-67226RabbitMQ: Admin-only atom exhaustion: PUT /api/users tags list

Updated under an hour ago (2026-10-19 09:10 UTC)

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It affects rabbitmq-server. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 6.9 MEDIUM (v4.0, CNA)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
Weakness (CWE): CWE-400
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Undergoing Analysis
Record last updated: Sep 25, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

rabbitmq rabbitmq-server rabbitmq:server (from the name)	from 4.0.0, < 4.0.22; from 4.1.0, < 4.1.14; from 4.2.0, < 4.2.7	CNA record

References

https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-34c7-r8w9-5wv8x-refsource-confirm
https://github.com/rabbitmq/rabbitmq-server/commit/86601c5a6d1c7e41060e3dbd165c88bdc91266eex-refsource-misc
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.