CVE-2026-57216: RabbitMQ authentication bypass for loopback-restricted users

CVE-2026-57216 · Severity: medium · CVSS 6.8 · Published 2026-07-10

RabbitMQ is a widely used messaging broker that facilitates communication between different software applications. A security flaw in how it handles certain network protocols could allow restricted users, such as the default 'guest' account, to connect to the server remotely even when they are supposed to be limited to local access only. This could lead to unauthorized access to sensitive message data if the server is configured to trust certain network proxy traffic.

Technologies: Broadcom Rabbitmq Server. Vendors: Broadcom.

Quick answers

Is CVE-2026-57216 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-57216 being exploited in the wild.
How severe is CVE-2026-57216?
Medium severity, with a CVSS score of 6.8, published 10 July 2026.
Which products and versions are affected?
Broadcom Rabbitmq Server >= 3.13.0, < 3.13.15; >= 4.0.0, < 4.0.21; >= 4.1.0, < 4.1.11; >= 4.2.0, < 4.2.6.
Is there a fix for CVE-2026-57216?
A patch was published on 2026-04-06: Fix merged into main branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-57216 attacked?
It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-57216?
Check whether you run Broadcom Rabbitmq Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An authentication bypass vulnerability exists in RabbitMQ's handling of AMQP 0-9-1, AMQP 1.0, and Stream Protocol connections. The root cause is an incorrect loopback check that utilizes the listener-side socket address (sockname) instead of the actual client source address (peername) when traffic is received through a trusted PROXY-protocol path. This allows users restricted to loopback interfaces (like the default 'guest' user) to bypass these restrictions and connect from remote network locations. The vulnerability is present when the backend listener is bound to a loopback address but receives proxied traffic. It has been addressed by updating the check to use the correct peer identity.

Affected products

  • RabbitMQ RabbitMQ Server >= 3.13.0, < 3.13.15; >= 4.0.0, < 4.0.21; >= 4.1.0, < 4.1.11; >= 4.2.0, < 4.2.6

Timeline

  • 2026-07-10: advisory: NVD publication date
  • 2026-04-06: patched: Fix merged into main branch

References

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