RabbitMQ up to 4.3.0 OAuth2 Scope rabbitdatacoercion:toatom resource consumption

Summaryinfo

A vulnerability was found in RabbitMQ up to 3.13.14/4.0.21/4.1.10/4.2.5/4.3.0. It has been declared as critical. This affects the function rabbitdatacoercion:toatom of the component OAuth2 Scope Handler. The manipulation results in resource consumption. This vulnerability is identified as CVE-2026-66071. The attack can be executed remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in RabbitMQ up to 3.13.14/4.0.21/4.1.10/4.2.5/4.3.0. Affected is the function rabbitdatacoercion:toatom of the component OAuth2 Scope Handler. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-66071 since 07/24/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 3.13.15, 4.0.22, 4.1.11, 4.2.6 or 4.3.1 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

• RabbitMQ

Version

• 3.13.0
• 3.13.1
• 3.13.2
• 3.13.3
• 3.13.4
• 3.13.5
• 3.13.6
• 3.13.7
• 3.13.8
• 3.13.9
• 3.13.10
• 3.13.11
• 3.13.12
• 3.13.13
• 3.13.14
• 4.0
• 4.0.0
• 4.0.1
• 4.0.2
• 4.0.3
• 4.0.4
• 4.0.5
• 4.0.6
• 4.0.7
• 4.0.8
• 4.0.9
• 4.0.10
• 4.0.11
• 4.0.12
• 4.0.13
• 4.0.14
• 4.0.15
• 4.0.16
• 4.0.17
• 4.0.18
• 4.0.19
• 4.0.20
• 4.0.21
• 4.1
• 4.1.0
• 4.1.1
• 4.1.2
• 4.1.3
• 4.1.4
• 4.1.5
• 4.1.6
• 4.1.7
• 4.1.8
• 4.1.9
• 4.1.10
• 4.2
• 4.2.0
• 4.2.1
• 4.2.2
• 4.2.3
• 4.2.4
• 4.2.5
• 4.3.0

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