Medium 6.0Published Sep 25, 2026

CVE-2026-66071RabbitMQ: Atom exhaustion: OAuth2 JWT tag: scope values

Updated under an hour ago (2026-10-19 07:50 UTC)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for rabbitmq-server

Exploited in the last 30 days

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.15 and 4.0.22 and 4.1.11 and 4.2.6 and 4.3.1, Atom exhaustion: OAuth2 JWT tag: scope values. extractscopes/1 parses scopes of the form .tag: and calls rabbitdatacoercion:toatom() to convert to a tag atom. The token signature is verified first, so the attacker cannot forge scopes , but in IdP configurations where scope content is user-influenced, each login with a novel tag value leaks one In deployments where users can influence the scopes included in their IdP-issued JWT rabbitmqauthbackendoauth2 enabled IdP permits attacker-influenced scope values in signed tokens. This issue is fixed in versions 3.13.15 and 4.0.22 and 4.1.11 and 4.2.6 and 4.3.1.

CVSS: 6.0 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:L/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: Analyzed
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 3.13.0, < 3.13.15; from 4.0.0, < 4.0.22; from 4.1.0, < 4.1.11; from 4.2.0, < 4.2.6; from 4.3.0, < 4.3.1	CNA record
broadcom rabbitmq_server broadcom:rabbitmq_server	from 3.13.0 before 3.13.15; from 4.0.0 before 4.0.22; from 4.1.0 before 4.1.11; from 4.2.0 before 4.2.6; from 4.3.0 before 4.3.1	NVD

References

https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-89p2-f5cv-x5cgx-refsource-confirm, exploit, third-party-advisory
https://github.com/rabbitmq/rabbitmq-server/commit/9a44124d9c932d6fc7d2a3b945e5a143e547bcb6x-refsource-misc, patch
https://github.com/rabbitmq/rabbitmq-server/commit/c5690583a53789a3bf00cca508b43e8246db0d11x-refsource-misc, patch
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6x-refsource-misc, release-notes
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1x-refsource-misc, release-notes

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.