CVE-2026-44838

RabbitMQ is a messaging and streaming broker. From 4.2.0 to before 4.2.4, RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{client_id}-sensors$ to restrict user access to topics that include their client ID. However, the client_id is provided by the user in the MQTT CONNECT packet and is inserted into the regex pattern without escaping special regex characters. This flaw enables an authenticated MQTT user to inject regex operators to bypass authorization. This vulnerability is fixed in 4.2.4 and 4.3.0.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-x866-xp2g-cx8v	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:broadcom:rabbitmq_server:*:*:*:*:*:*:*:*

History

26 Oct 2026, 11:10

Type	Values Removed	Values Added
Summary		(es) RabbitMQ es un broker de mensajería y streaming. Desde 4.2.0 hasta antes de 4.2.4, el plugin MQTT de RabbitMQ permite la autorización a nivel de tema utilizando expresiones regulares con sustitución de variables. Los administradores pueden crear patrones como ^{client_id}-sensors$ para restringir el acceso de los usuarios a temas que incluyan su ID de cliente. Sin embargo, el client_id es proporcionado por el usuario en el paquete MQTT CONNECT y se inserta en el patrón de regex sin escapar caracteres especiales de regex. Este fallo permite a un usuario MQTT autenticado inyectar operadores de regex para eludir la autorización. Esta vulnerabilidad se corrige en 4.2.4 y 4.3.0.

Information

Published : 2026-05-27 15:16

Updated : 2026-10-26 11:10

NVD link : CVE-2026-44838

Mitre link : CVE-2026-44838

CVE.ORG link : CVE-2026-44838

JSON object : View

Products Affected

broadcom

rabbitmq_server

CWE

CWE-863

Incorrect Authorization

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