Description
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.
Affected products
broadcom: rabbitmq server
References6
- github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r… ExploitVendor Advisory
- github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r… ExploitVendor Advisory
- github.com/rabbitmq/rabbitmq-server/commit/a7528314840c4f8dc990… Patch
- github.com/rabbitmq/rabbitmq-server/commit/edbead0eabbd65925d0d… Patch
- github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9 Release Notes
- github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3 Release Notes
Metrics
- CVSS 3.1
-
7.1
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N - CVSS 4.0
-
6.0
MEDIUM
Score source: CNA
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 - EPSS — exploit probability
- 0% percentile: 25 · as of 9 November 2026
- CWE
- CWE-863
Could this be exploited in your environment?
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