CVE-2019-6829
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 · uneditedA CWE-248: Uncaught Exception vulnerability exists in Modicon M580 (firmware version prior to V2.90) and Modicon M340 (firmware version prior to V3.10), which could cause a possible denial of service when writing to specific memory addresses in the controller over Modbus.
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 confidenceAn uncaught exception vulnerability (CWE-248) in Schneider Electric Modicon M580 (firmware <V2.90) and Modicon M340 (firmware <V3.10) PLCs allows remote attackers to cause denial of service by writing to specific memory addresses over the Modbus protocol. The unhandled exception crashes the controller, requiring manual restart.
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< 2.90< 3.10CVSS 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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Identify PLC modelLocate the physical PLC hardware or check engineering documentation to confirm whether the device is a Modicon M580 or Modicon M340 controller.Affected if The device is a Modicon M580 or Modicon M340 PLC.
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Check Modicon M580 firmware versionAccess the PLC via EcoStruxure Control Expert (formerly Unity Pro) or check the firmware version through the web interface or system diagnostic. Compare the installed version against V2.90.Affected if Firmware version is below 2.90 on a Modicon M580.
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Check Modicon M340 firmware versionAccess the PLC via EcoStruxure Control Expert (formerly Unity Pro) or check the firmware version through the web interface or system diagnostic. Compare the installed version against V3.10.Affected if Firmware version is below 3.10 on a Modicon M340.
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Verify Modbus protocol is enabledCheck PLC configuration in EcoStruxure Control Expert or through the PLC's network settings to determine if Modbus (Modbus TCP or Modbus Serial) communication is enabled and configured.Affected if Modbus protocol is enabled and accessible on the network.
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Assess network accessibility of Modbus serviceReview network segmentation and firewall rules to determine if the PLC's Modbus port (typically TCP/502) is reachable from unauthorized network segments or external systems.Affected if The Modbus service is exposed to untrusted network segments.
A user is affected if they have a Modicon M580 with firmware below V2.90 or a Modicon M340 with firmware below V310, and Modbus protocol is enabled and network-accessible to potential attackers.
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 data2.903.10
Upgrade Modicon M580 firmware to V2.90 or later, and Modicon M340 firmware to V3.10 or later. Implement network segmentation to restrict Modbus access to authorized systems only.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-6829 — 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-2019-6829 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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