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OpenAdvisories
Medium · 6.0 CVE-2026-66071 EUVD-2026-87151

RabbitMQ: Atom exhaustion: OAuth2 JWT tag: scope values

Published Sep 25, 2026 · Updated Sep 25, 2026 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
rabbitmq rabbitmq-server >= 3.13.0, < 3.13.15, >= 4.0.0, < 4.0.22, >= 4.1.0, < 4.1.11, >= 4.2.0, < 4.2.6, >= 4.3.0, < 4.3.1 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 rabbitmq-server 4.3.2-1 —
Debian 13 rabbitmq-server No fix yet —
Debian 12 rabbitmq-server No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.04 LTS rabbitmq-server No fix yet —
Ubuntu 24.04 LTS rabbitmq-server No fix yet —
Ubuntu 22.04 LTS rabbitmq-server No fix yet —
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 20.04 LTS rabbitmq-server No fix yet —
Ubuntu Pro 18.04 LTS rabbitmq-server No fix yet —
Ubuntu Pro 16.04 LTS rabbitmq-server No fix yet —
ReleasePackageFixed inAdvisory
Red Hat Hardened Images 1 rabbitmq-server4.3 4.3.6-1.hum1 RHSA-2026:67552

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 rabbitmq-server 3.13.7-10 —

Advisories 1

References