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Missing AuthenticationWeakness · CWE-306

CVE-2023-1083

CRITICAL · 9.8 CVSS v3.1 Published 2024-04-09
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 unauthenticated remote attacker who is aware of a MQTT topic name can send and receive messages, including GET/SET configuration commands, reboot commands and firmware updates.

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 · moderate confidence

This is an MQTT (Message Queuing Telemetry Transport) broker vulnerability where unauthenticated attackers who know a topic name can publish and subscribe to it without any access control. This allows remote attackers to send GET/SET configuration commands, issue reboot commands, and push firmware updates to affected devices, achieving full remote compromise without credentials.

MitigationImplement MQTT broker authentication (e.g., username/password, certificates) and configure topic-level access control lists (ACLs) to restrict who can publish/subscribe to specific topics. Add command validation and authorization checks before executing any received configuration, reboot, or firmware commands.

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

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:3.1/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. Identify MQTT broker in use
    Run 'ps aux | grep -i mqtt' or check running services on ports 1883 (MQTT) or 8883 (MQTTS) to determine if an MQTT broker is running
    Affected if An MQTT broker is running and accessible on the network without prior identification of its type or version
  2. Check if anonymous/mixed authentication is enabled
    Inspect the MQTT broker configuration file (e.g., mosquitto.conf for Mosquitto, emqx.conf for EMQ X, broker.conf for HiveMQ) for settings like 'allow_anonymous true' or authentication disabled
    Affected if The broker allows anonymous connections or has no authentication mechanism configured
  3. Verify ACL configuration exists
    Review the broker configuration for ACL file references (e.g., 'acl_file' in Mosquitto) and inspect the ACL rules to determine which topics are accessible without credentials
    Affected if No ACL rules are defined or configured, allowing any client to publish/subscribe to any topic
  4. Test unauthenticated topic access
    Use an MQTT client tool (e.g., mosquitto_pub/mosquitto_sub, mqtt-explorer) to connect to the broker without credentials and attempt to subscribe to a known test topic, or enumerate accessible topics
    Affected if Connection succeeds without authentication and topics can be published to or subscribed from without credentials
  5. Check broker network exposure
    Run 'netstat -tlnp | grep 1883' or 'ss -tlnp | grep 1883' to determine if the MQTT port is bound to 0.0.0.0 or an external interface rather than localhost only
    Affected if The MQTT broker is listening on all interfaces (0.0.0.0) or an external IP address, making it reachable from untrusted networks
  6. Review authentication backend configuration
    Examine the broker configuration for authentication plugin settings, password file configuration (e.g., 'password_file' in Mosquitto), or certificate-based authentication setup
    Affected if No password file, certificate authentication, or authentication plugin is configured, or the configured authentication is disabled/inoperative

The environment is affected if an MQTT broker is running without enforced authentication (anonymous access allowed) and without ACL rules restricting topic publish/subscribe access to unauthorized clients.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement MQTT broker authentication (e.g., username/password, certificates) and configure topic-level access control lists (ACLs) to restrict who can publish/subscribe to specific topics. Add command validation and authorization checks before executing any received configuration, reboot, or firmware commands.

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
36.0 hours of engineering $6,400
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Scan for this in your stack

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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-2023-1083 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data