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Rabbitmq server: RabbitMQ is a messaging and streaming broker. (CVE-2026-66071)

0
Medium
VulnerabilityCVE-2026-66071gcveosvubuntu-cve-2026-66071cve-2026-66071ubuntu-pro-16-04-ltsubuntu-pro-18-04-ltsubuntu-pro-20-04-ltsubuntu-22-04-ltsubuntu-24-04-ltsubuntu-26-04-lts
Published: 09/25/2026 (09/25/2026, 17:17:00 UTC)
Source: GCVE Database
Product: rabbitmq-server

Description

CVE-2026-66071 is a medium severity vulnerability in RabbitMQ server versions from 3.13.0 up to 3.13.15 and several 4.x versions. It involves atom exhaustion caused by parsing OAuth2 JWT scope values influenced by users in certain IdP configurations. The vulnerability allows leaking of atom tags during login with novel scope values. This issue is fixed in RabbitMQ versions 3.13.15, 4.0.22, 4.1.11, 4.2.6, and 4.3.1.

CVSS v3.1

Score 6.5medium

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected software

Ubuntu:Pro:16.04:LTSmore threats →ghsa
rabbitmq-server
pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=esm-infra-legacy/xenial
Affected versions
=3.5.4-1=3.5.4-3=3.5.4-3.1=3.5.7-1=3.5.7-1ubuntu0.16.04.1=3.5.7-1ubuntu0.16.04.2=3.5.7-1ubuntu0.16.04.4=3.5.7-1ubuntu0.16.04.4+esm1=3.5.7-1ubuntu0.16.04.4+esm2=3.5.7-1ubuntu0.16.04.4+esm3
Ubuntu:Pro:18.04:LTSmore threats →ghsa
rabbitmq-server
pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=esm-infra/bionic
Affected versions
=3.6.10-1=3.6.10-1ubuntu0.1=3.6.10-1ubuntu0.3=3.6.10-1ubuntu0.4=3.6.10-1ubuntu0.5=3.6.10-1ubuntu0.5+esm1
Ubuntu:Pro:20.04:LTSmore threats →ghsa
rabbitmq-server
pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=esm-infra/focal
Affected versions
=3.7.8-4ubuntu2=3.7.18-1=3.8.2-0ubuntu1=3.8.2-0ubuntu1.1=3.8.2-0ubuntu1.2=3.8.2-0ubuntu1.3=3.8.2-0ubuntu1.4=3.8.2-0ubuntu1.5=3.8.3-0ubuntu0.1=3.8.3-0ubuntu0.2=3.8.3-0ubuntu0.3=3.8.3-0ubuntu0.3+esm1=3.8.3-0ubuntu0.3+esm2
Ubuntu:22.04:LTSmore threats →ghsa
rabbitmq-server
pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=jammy
Affected versions
=3.8.9-3ubuntu1=3.9.8-1=3.9.8-2=3.9.8-3=3.9.8-5=3.9.8-6=3.9.13-1=3.9.13-1ubuntu0.22.04.1=3.9.13-1ubuntu0.22.04.2=3.9.27-0ubuntu0.1=3.9.27-0ubuntu0.2=3.9.27-0ubuntu0.5=3.9.27-0ubuntu0.6
Ubuntu:24.04:LTSmore threats →ghsa
rabbitmq-server
pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=noble
Affected versions
=3.12.1-1=3.12.1-1ubuntu1=3.12.1-1ubuntu1.2=3.12.1-1ubuntu1.4=3.12.1-1ubuntu1.6=3.12.1-1ubuntu1.7
Ubuntu:26.04:LTSmore threats →ghsa
rabbitmq-server
pkg:deb/ubuntu/rabbitmq-server?arch=source&distro=resolute
Affected versions
=4.0.5-8ubuntu2=4.0.5-10ubuntu1=4.0.5-10ubuntu2=4.0.5-10ubuntu3=4.0.5-10ubuntu4=4.0.5-10ubuntu5=4.0.5-10ubuntu5.1=4.0.5-10ubuntu5.2

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 10/18/2026, 00:09:07 UTC

Technical Analysis

RabbitMQ server versions 3.13.0 through 3.13.15 and 4.0.0 through 4.3.1 are affected by an atom exhaustion vulnerability (CVE-2026-66071) related to the OAuth2 JWT scope parsing mechanism. The function extractscopes/1 parses scope values of the form .tag: and converts them to atoms via rabbitdatacoercion:toatom(). Because the token signature is verified, attackers cannot forge scopes, but in Identity Provider (IdP) configurations where scope content is user-influenced, each login with a novel tag value leaks one atom tag. This can lead to atom exhaustion, potentially causing denial of service. The vulnerability is fixed in versions 3.13.15, 4.0.22, 4.1.11, 4.2.6, and 4.3.1.

Potential Impact

The vulnerability can cause atom exhaustion in RabbitMQ servers when processing OAuth2 JWT tokens with user-influenced scope values. This may lead to denial of service (application crash or resource exhaustion). There is no impact on confidentiality or integrity as token signatures are verified and scopes cannot be forged. The attack requires an IdP configuration that permits attacker-influenced scope values in signed tokens.

Mitigation Recommendations

Upgrade RabbitMQ to versions 3.13.15, 4.0.22, 4.1.11, 4.2.6, or 4.3.1 where this vulnerability is fixed. No other mitigations are indicated. Patch status is confirmed fixed in these versions.

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Technical Details

Gcve Source
db.gcve.eu
Osv Id
UBUNTU-CVE-2026-66071
Osv Schema Version
1.7.0
Ecosystems
["Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.04:LTS"]
Cvss Version
3.1
State
PUBLISHED

Threat ID: 6ad3f5b12cdf04f656662826

Added to database: 10/17/2026, 22:24:49 UTC

Last enriched: 10/18/2026, 00:09:07 UTC

Last updated: 10/18/2026, 00:09:07 UTC

Views: 2

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