CVE-2019-13120
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 · uneditedAmazon FreeRTOS up to and including v1.4.8 lacks length checking in prvProcessReceivedPublish, resulting in untargetable leakage of arbitrary memory contents on a device to an attacker. If an attacker has the authorization to send a malformed MQTT publish packet to an Amazon IoT Thing, which interacts with an associated vulnerable MQTT message in the application, specific circumstances could trigger this vulnerability.
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 confidenceAmazon FreeRTOS up to v1.4.8 contains a memory disclosure vulnerability in the MQTT message handler (prvProcessReceivedPublish). The lack of length validation when processing incoming MQTT publish packets allows an authenticated attacker who can send packets to an IoT Thing to read arbitrary device memory contents beyond the intended message buffer.
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<= 1.4.8CVSS 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
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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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Identify Amazon FreeRTOS deploymentDetermine if your IoT device runs Amazon FreeRTOS as its embedded operating system. Check device documentation, firmware build files, or system information for 'Amazon FreeRTOS' or 'FreeRTOS' branding.Affected if The device does not run Amazon FreeRTOS, then it is not affected by this specific CVE.
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Determine the FreeRTOS versionLocate the version string in your deployed firmware. This may be in firmware metadata, boot logs, version headers (typically in a version.h or freertos_version.h file within the source tree), or in the firmware image string table.Affected if The installed version is 1.4.8 or earlier; if your version is unknown but confirmed <=1.4.8, you are affected. Versions greater than 1.4.8 are not vulnerable.
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Verify MQTT is enabledCheck your FreeRTOS configuration to determine if the MQTT client module is compiled and active. Look for configuration flags such as configMQTT_LIBRARY_ENABLED, inclusion of the MQTT agent or MQTT core library in your build, or network stack configuration exposing MQTT ports (typically 8883 or 1883).Affected if MQTT is not compiled into your firmware, the vulnerable code path is not present and the device is not affected.
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Confirm network exposure to MQTTDetermine if the device's MQTT endpoint is accessible from untrusted networks. Review firewall rules, network segmentation, and ACLs governing access to the device's MQTT listener. Assess whether an attacker can inject packets to the device without authentication bypass.Affected if The MQTT handler is present but network access is strictly limited to trusted parties via authenticated TLS, the practical exploitability is reduced, though the code flaw still exists in the binary.
You are affected if your device runs Amazon FreeRTOS version 1.4.8 or earlier with the MQTT client module enabled and network-accessible MQTT endpoints.
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.
From vendor dataUpgrade Amazon FreeRTOS to a version beyond v1.4.8 that contains the patch. If upgrading is not feasible, implement application-layer validation of MQTT message lengths before processing and restrict MQTT endpoint access to prevent unauthorized packet injection.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-13120 — 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-2019-13120 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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