RabbitMQ 4.2.x < 4.2.4 MQTT Topic Authorization Bypass

high Nessus Plugin ID 327579

Synopsis

The RabbitMQ installed on the remote host is affected by a vulnerability.

Description

The version of RabbitMQ installed on the remote host is 4.2.x prior to 4.2.4. It is, therefore, affected by an authorization bypass vulnerability:

- RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution.
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. (CVE-2026-44838)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Upgrade to RabbitMQ version 4.2.4 or later.

Plugin Details

Severity: High

ID: 327579

File Name: rabbitmq_4_2_4.nasl

Version: 1.1

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 7/17/2026

Updated: 7/17/2026

Configuration: Enable paranoid mode, Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.62

CVSS v2

Risk Factor: High

Base Score: 8.5

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:N

CVSS Score Source: CVE-2026-44838

CVSS v3

Risk Factor: High

Base Score: 8.1

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Vulnerability Information

CPE: cpe:/a:vmware:rabbitmq, cpe:/a:pivotal_software:rabbitmq

Required KB Items: installed_sw/RabbitMQ, Settings/ParanoidReport

Patch Publication Date: 5/27/2026

Vulnerability Publication Date: 5/27/2026

Reference Information

CVE: CVE-2026-44838

Detections

Analytics