dbcve.org
Rabbitmq ServerApplication · Broadcom

CVE-2016-9877

CRITICAL · 9.8 CVSS v3.0 Published 2016-12-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
An issue was discovered in Pivotal RabbitMQ 3.x before 3.5.8 and 3.6.x before 3.6.6 and RabbitMQ for PCF 1.5.x before 1.5.20, 1.6.x before 1.6.12, and 1.7.x before 1.7.7. MQTT (MQ Telemetry Transport) connection authentication with a username/password pair succeeds if an existing username is provided but the password is omitted from the connection request. Connections that use TLS with a client-provided certificate are not affected.

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

MQTT plugin in RabbitMQ has an authentication bypass vulnerability where providing a valid username without any password successfully authenticates the connection. This allows unauthorized access to the messaging broker via the MQTT protocol.

MitigationUpgrade RabbitMQ to version 3.5.8+, 3.6.6+, or the corresponding PCF versions (1.5.20+, 1.6.12+, 1.7.7+). Until patched, ensure MQTT is not exposed to untrusted networks.

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:= 3.0.0= 3.0.1= 3.0.2= 3.0.3= 3.0.4= 3.1.0= 3.1.1= 3.1.2= 3.1.3= 3.1.4= 3.1.5= 3.2.0
RabbitmqApplication
Affected:= 3.5.4= 3.5.5= 3.5.7= 3.6.0= 3.6.1= 3.6.2= 3.6.3= 3.6.4= 3.6.5= 1.5.0= 1.5.1= 1.5.2

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/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. Verify RabbitMQ version
    Run `rabbitmqctl status` or check the management UI to find the installed RabbitMQ version
    Affected if Version matches 3.0.0-3.2.0, 3.5.4-3.5.7, 3.6.0-3.6.5, or 1.5.0-1.5.2
  2. Confirm MQTT plugin is enabled
    Run `rabbitmq-plugins list` and look for the MQTT plugin (rabbitmq_mqtt) in the enabled list
    Affected if MQTT plugin is enabled and version is in the affected range
  3. Check if MQTT listener is configured
    Inspect RabbitMQ config file (rabbitmq.conf or advanced.config) or run `rabbitmqctl list_listeners` to see if port 1883 (MQTT) or 8883 (MQTT/SSL) is listening
    Affected if MQTT port is open and listening, and version is affected
  4. Verify MQTT authentication settings
    Check the MQTT plugin configuration in the config file for the `mqtt.default_user` or `mqtt.allow_empty_password` settings
    Affected if MQTT plugin is configured and accepts connections without password validation

User is affected if RabbitMQ version is in the affected list, the MQTT plugin is enabled, and the MQTT listener is exposed - in this case, any connection with a valid username but no password can authenticate successfully.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade RabbitMQ to version 3.5.8+, 3.6.6+, or the corresponding PCF versions (1.5.20+, 1.6.12+, 1.7.7+). Until patched, ensure MQTT is not exposed to untrusted networks.

Recommended fix High confidence

Upgrade to RabbitMQ 3.5.8+ or 3.6.6+ (3.6.x recommended for latest features and support)

  1. 1. Identify the current RabbitMQ version by running 'rabbitmqctl status' or checking the management UI
  2. 2. Determine the appropriate upgrade path based on your current version and infrastructure requirements
  3. 3. Back up RabbitMQ configuration files (rabbitmq.conf, advanced.config) and persistent data directories
  4. 4. For RabbitMQ 3.0.x: Upgrade directly to 3.5.8 or later, or to 3.6.6+ for longer-term support
  5. 5. For RabbitMQ 3.5.x (3.5.4-3.5.7): Upgrade to 3.5.8 or later
  6. 6. For RabbitMQ 3.6.0: Upgrade to 3.6.6 or later
  7. 7. After upgrade, verify the fix by testing MQTT authentication: confirm that connections with valid username but omitted password are now rejected
  8. 8. Ensure any automated scripts or applications using MQTT connections now include the password
Caveat Review release notes for breaking changes between 3.0.x/3.5.x and 3.6.x, particularly around Erlang version requirements and plugin compatibility

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

Fix this in Rabbitmq Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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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-2016-9877 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data