CVE-2023-3592
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 · uneditedIn Mosquitto before 2.0.16, a memory leak occurs when clients send v5 CONNECT packets with a will message that contains invalid property types.
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 confidenceMosquitto MQTT broker versions before 2.0.16 contain a memory leak vulnerability in the v5 CONNECT packet handling logic. When a client sends a CONNECT packet with a will message that contains invalid property types, memory allocated for the will message is not properly freed, leading to gradual memory exhaustion over time with repeated malformed requests.
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< 2.0.16CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Check Mosquitto versionRun `mosquitto --version` or check the package manager (e.g., `dpkg -l mosquitto`, `rpm -qi mosquitto`)Affected if Version is below 2.0.16
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Identify running Mosquitto processRun `ps aux | grep mosquitto` or check system service status (e.g., `systemctl status mosquitto`)Affected if Mosquitto is running and version is below 2.0.16
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Check if MQTT v5 protocol is enabledInspect the Mosquitto configuration file (typically `/etc/mosquitto/mosquitto.conf` or `/etc/mosquitto/conf.d/`) for `protocol_version mqttv5` or default v5 behaviorAffected if MQTT protocol version 5 is accepted (the flaw is in v5 CONNECT packet handling)
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Monitor memory usage of the Mosquitto processUse tools like `ps -o rss= -p <pid>` or monitor via system tools (top, htop, /proc/<pid>/status) over time with repeated connectionsAffected if Memory usage grows steadily without release when receiving malformed v5 CONNECT packets with invalid will properties
A system is affected if it runs Mosquitto version below 2.0.16, accepts MQTT v5 connections, and an attacker can send malformed CONNECT packets with invalid will message properties.
Generated from the published advisory. Verify against your own configuration.
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 · scoped2.0.16
Upgrade Mosquitto to version 2.0.16 or later. If immediate upgrade is not feasible, implement network-level rate limiting and connection throttling to reduce the impact of potential DoS via repeated malformed packets.
Mosquitto 2.0.16
- 1. Identify your current Mosquitto version using: mosquitto -version or dpkg -l | grep mosquitto / rpm -qa | grep mosquitto
- 2. Stop the Mosquitto broker service: sudo systemctl stop mosquitto
- 3. Upgrade Mosquitto to version 2.0.16 or later. For source compilation, download from mosquitto.org or check your distribution's package manager for the updated package.
- 4. Verify the installation: mosquitto -version
- 5. Restart the Mosquitto service: sudo systemctl start mosquitto
- 6. Monitor system memory to confirm the memory leak is resolved.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,904.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-3592 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-3592 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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