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Fencer Vulns
high 7.1

CVE-2026-67411 json

RabbitMQ: Web MQTT with PROXY Protocol enabled: a loopback-only user permission bypass

published 2026-09-25 44 d ago modified 2026-10-09 31 d ago also BIT-rabbitmq-2026-67411 , EUVD-2026-87229 , GHSA-4r6f-9cpw-f6g6

cvss
7.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3, native MQTT and MQTT over WebSocket behind a trusted PROXY Protocol frontend could lose the proxy-derived client address before the MQTT authentication path checked loopback_users, causing the frontend-to-broker address to be treated as loopback. An attacker who can reach the trusted frontend and has valid credentials for a loopback-restricted account can therefore bypass the source-address restriction; the issue does not bypass password authentication. This issue is fixed in versions 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3.

Patch / fix

  • bitnami rabbitmq 3.13.18, 4.0.23, 4.1.14, 4.2.9, 4.3.3
  • pivotal_software rabbitmq 3.13.18, 4.0.23, 4.1.14, 4.2.9, 4.3.3
  • vmware rabbitmq 3.13.18, 4.0.23, 4.1.14, 4.2.9, 4.3.3
  • rabbitmq-server Debian 14 4.3.6-1

debian advisories DEBIAN-CVE-2026-67411

  • rabbitmq-server4.3 hummingbird 1 4.3.6-1.hum1

red hat advisories RHSA-2026:67552

  • rabbitmq-server Azure Linux 3.0 3.13.7-10

azure linux advisories AZL-105296

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-67411 updated cvss 5.3

rabbitmq-server: rabbitmq-server: Access control bypass via PROXY protocol handling in MQTT

  • Red Hat Hardened Images rabbitmq-server4.2 4.2.9-0.2.hum1
    affected: no fix planned “Will not fix”
  • Red Hat OpenStack Platform 13 (Queens) rabbitmq-server Red Hat OpenStack Platform 16.2 rabbitmq-server Red Hat OpenStack Platform 17.1 rabbitmq-server
    affected: no fix planned “Out of support scope”
  • Red Hat OpenStack Platform 18.0 rabbitmq-server
    affected: no fix available “Fix deferred”
  • Red Hat Hardened Images rabbitmq-server4.3 4.3.6-1.hum1
    fixed: vendor fix RHSA-2026:67552

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
44 d ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r6f-9cpw-f6g6 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.0 CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 4.0 6.0 CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
OSV 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Affected packages

ecosystem package affected fixed in
bitnami rabbitmq
>=3.13.0, <3.13.18
>=4.0.0, <4.0.23
>=4.1.0, <4.1.14
>=4.2.0, <4.2.9
>=4.3.0, <4.3.3
3.13.18
4.0.23
4.1.14
4.2.9
4.3.3

Affected products

  • rabbitmq rabbitmq-server

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.