Detections
Analytics

RabbitMQ 4.2.x < 4.2.4 MQTT Topic Authorization Bypass

medium Nessus Plugin ID 327579

Language:

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.

See Also

http://www.nessus.org/u?053086c7

Plugin Details

Severity: Medium

ID: 327579

File Name: rabbitmq_4_2_4.nasl

Version: 1.3

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 7/17/2026

Updated: 7/20/2026

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

Temporal Score: 6.3

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

Temporal Score: 7.1

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 5.3

Threat Score: 1.3

Threat Vector: CVSS:4.0/E:U

Vector: 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

Vulnerability Information

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

Required KB Items: Settings/ParanoidReport, installed_sw/RabbitMQ

Exploit Ease: No known exploits are available

Patch Publication Date: 5/27/2026

Vulnerability Publication Date: 5/27/2026

Reference Information

CVE: CVE-2026-44838

IAVA: 2026-A-0683