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CVE-2026-44838— RabbitMQ MQTT Topic Permission Authorization Bypass

Quick assessment

Affected
rabbitmq rabbitmq-server
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

RabbitMQ是RabbitMQ开源的一个功能丰富的多协议消息和流媒体代理。 RabbitMQ 4.2.0至4.2.4之前版本存在安全漏洞，该漏洞源于MQTT插件中的主题级授权使用正则表达式进行变量替换，但client_id由用户提供且未转义特殊正则字符，导致认证的MQTT用户可注入正则运算符绕过授权。

AI Predicted 7.5 Difficulty: Easy EPSS 0.25% · P16

Affected Version Matrix 1

VendorProduct Version RangeStatus
rabbitmq rabbitmq-server >= 4.2.0, < 4.2.4 affected
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I. Basic Information for CVE-2026-44838

Vulnerability Information
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Vulnerability Title
RabbitMQ MQTT Topic Permission Authorization Bypass
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:H/SI:H/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制不正确
Source: CVE Program / CVE List V5
Vulnerability Title
RabbitMQ 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
RabbitMQ是RabbitMQ开源的一个功能丰富的多协议消息和流媒体代理。 RabbitMQ 4.2.0至4.2.4之前版本存在安全漏洞，该漏洞源于MQTT插件中的主题级授权使用正则表达式进行变量替换，但client_id由用户提供且未转义特殊正则字符，导致认证的MQTT用户可注入正则运算符绕过授权。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
rabbitmq rabbitmq-server >= 4.2.0, < 4.2.4 -

II. Public POCs for CVE-2026-44838

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III. Intelligence Information for CVE-2026-44838

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Vendor Advisories for CVE-2026-44838 (1)

IV. Related Vulnerabilities

Same product: rabbitmq-server
Same vendor: rabbitmq
Same weakness: CWE-863

V. Comments for CVE-2026-44838

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