CVE-2026-66071

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.

• CWE-400

• https://github.com/rabbitmq/rabbitmq-server/commit/9a44124d9c932d6fc7d2a3b945e5a143e547bcb6Patch
• https://github.com/rabbitmq/rabbitmq-server/commit/c5690583a53789a3bf00cca508b43e8246db0d11Patch
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6Release Notes
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1Release Notes
• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-89p2-f5cv-x5cgExploit, Third Party Advisory

Published

Sep 25, 2026

Last Modified

Oct 15, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-66066Action Pack is a framework for handling and responding to we…9.5
• CVE-2026-66067RabbitMQ is a messaging and streaming broker. Prior to versi…6.5
• CVE-2026-66068RabbitMQ is a messaging and streaming broker. Prior to versi…4.4
• CVE-2026-66069RabbitMQ is a messaging and streaming broker. Prior to versi…4.3
• CVE-2026-6607A security vulnerability has been detected in lm-sys fastcha…5.3
• CVE-2026-66070RabbitMQ is a messaging and streaming broker. Prior to versi…8.8
• CVE-2026-66072RabbitMQ is a messaging and streaming broker. Prior to versi…6.5
• CVE-2026-66073RabbitMQ is a messaging and streaming broker. From 3.13.0 un…6.5
• CVE-2026-66074RabbitMQ is a messaging and streaming broker. Prior to versi…6.5
• CVE-2026-66075RabbitMQ is a messaging and streaming broker. Prior to versi…5.4
• CVE-2026-66076RabbitMQ is a messaging and streaming broker. Prior to versi…6.5
• CVE-2026-66077RabbitMQ is a messaging and streaming broker. Prior to versi…6.1