CVE-2026-67411

UNKNOWN 0.0

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

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-863
Vendor	rabbitmq
Product	rabbitmq-server
Published	Sep 25, 2026
Last Updated	Sep 25, 2026

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Affected Versions

rabbitmq / rabbitmq-server

>= 4.3.0, < 4.3.3 >= 4.2.0, < 4.2.9 >= 4.1.0, < 4.1.14 >= 4.0.0, < 4.0.23 >= 3.13.0, < 3.13.18

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-4r6f-9cpw-f6g6 github.com: https://github.com/rabbitmq/rabbitmq-server/commit/a7528314840c4f8dc9904684f9f97ffa7aac6349 github.com: https://github.com/rabbitmq/rabbitmq-server/commit/edbead0eabbd65925d0dc914a22d6a29e155e646 github.com: https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9 github.com: https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3