dbcve.org
Rabbitmq ServerApplication · Broadcom

CVE-2026-57216

CRITICAL · 10.0 CVSS v3.1 Published 2026-07-10
Fix available
A fix is available. Upgrade to 4.2.6 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click Patch available 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
RabbitMQ is a messaging and streaming broker. Prior to 3.13.15, 4.0.20, 4.1.11, and 4.2.6, AMQP 0-9-1, AMQP 1.0, and Stream Protocol authentication can allow a loopback-restricted user such as guest to connect remotely when traffic is accepted through a trusted PROXY-protocol path and the backend listener is loopback-bound because the loopback check uses the listener-side socket address instead of the real client source. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

RabbitMQ has an authentication bypass where the loopback check for restricted users (like 'guest') uses the listener-side socket address instead of the real client source IP when PROXY-protocol is in use. This allows remote attackers to bypass loopback-only restrictions and connect as guest from remote locations through a trusted PROXY-protocol path.

MitigationUpgrade to RabbitMQ versions 3.13.15, 4.0.20, 4.1.11, or 4.2.6. Until then, avoid using PROXY-protocol with loopback-bound listeners that have restricted users like guest.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Rabbitmq ServerApplication
Affected:>= 3.13.0, < 4.2.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check RabbitMQ version
    Run `rabbitmqctl status` or check the version via `rabbitmq-server --version`. Compare the version number to the affected range: >= 3.13.0 and < 4.2.6
    Affected if The installed version falls within >= 3.13.0, < 4.2.6
  2. Verify PROXY-protocol is enabled
    Inspect the RabbitMQ configuration file (rabbitmq.conf or advanced.config) or run `rabbitmqctl list_listeners` to check for the `proxy_protocol` setting on any listener
    Affected if PROXY-protocol is enabled on any listener (proxy_protocol = true)
  3. Check listener binding address
    Run `rabbitmqctl list_listeners` to see which IP addresses each listener is bound to, or inspect the `listeners.tcp` configuration in rabbitmq.conf
    Affected if A listener is bound to a non-loopback address (0.0.0.0 or external IP) while PROXY-protocol is enabled
  4. Verify guest user loopback restriction
    Run `rabbitmqctl list_users` to confirm the 'guest' user exists, then check if loopback_users only setting is in effect (default restricts guest to localhost connections)
    Affected if The 'guest' user is configured with loopback-only restriction (loopback_users only setting is non-empty, which is the default)

A user is affected if their RabbitMQ version is >= 3.13.0 and < 4.2.6, PROXY-protocol is enabled on a listener bound to a non-loopback address, and the guest user retains its default loopback-only restriction.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.2.6 or later
Fixed in 4.2.6
Vendor patch github.com →
Interim mitigation

Upgrade to RabbitMQ versions 3.13.15, 4.0.20, 4.1.11, or 4.2.6. Until then, avoid using PROXY-protocol with loopback-bound listeners that have restricted users like guest.

Recommended fix High confidence

Upgrade to 4.2.6 (or the latest in your current major version branch: 3.13.15, 4.0.20, 4.1.11, or 4.2.6)

  1. 1. Identify the currently running RabbitMQ version using `rabbitmqctl status` or the management UI
  2. 2. Determine your current major version branch (3.13.x, 4.0.x, 4.1.x, or 4.2.x)
  3. 3. Stop the RabbitMQ service gracefully using `rabbitmqctl stop` or your system service manager
  4. 4. Backup your RabbitMQ configuration, data directory, and Erlang cookie files before upgrading
  5. 5. Install the appropriate fixed version for your branch: 3.13.15 for 3.13.x, 4.0.20 for 4.0.x, 4.1.11 for 4.1.x, or 4.2.6 for 4.2.x
  6. 6. Start the RabbitMQ service and verify it starts successfully
  7. 7. Verify the upgrade by checking the version with `rabbitmqctl version`
  8. 8. Test that authentication works correctly and loopback-restricted users (like guest) can only connect from localhost as expected
Caveat Review RabbitMQ upgrade notes for your version branch; major version upgrades may include breaking changes to features, APIs, or deprecated functionality

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Rabbitmq Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-57216 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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