CVE-2019-6809
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 versions prior to V2.90), Modicon M340 (firmware versions prior to V3.10), Modicon Premium (all versions), Modicon Quantum (all versions), which could cause a possible denial of service when reading invalid data from the controller.
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 confidenceThis is an uncaught exception vulnerability in Schneider Electric Modicon PLCs (M580, M340, Premium, Quantum) where reading invalid data from the controller triggers an unhandled exception, causing a denial of service. The vulnerability affects specific firmware versions across multiple product lines.
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< 3.10all versionsall versionsCVSS 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 the Modicon PLC model in your environmentLocate the physical PLC hardware or check your engineering workstation/project files for the controller type (M580, M340, Premium, or Quantum)Affected if The controller is a Modicon M580, M340, Premium, or Quantum PLC
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Determine the firmware version of the Modicon controllerAccess the PLC firmware version via the programming software (EcoStruxure Control Expert/Unity Pro) diagnostics, the PLC web server if enabled, or the project configurationAffected if Unable to confirm the firmware version, preventing comparison to safe versions
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Compare installed M580 firmware to the safe version thresholdIf the controller is Modicon M580, verify the firmware version is 2.90 or higherAffected if M580 firmware version is below 2.90
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Compare installed M340 firmware to the safe version thresholdIf the controller is Modicon M340, verify the firmware version is 3.10 or higherAffected if M340 firmware version is below 3.10
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Check if Premium or Quantum models are in useIdentify if any Modicon Premium or Quantum controllers are deployed in the environmentAffected if Modicon Premium or Quantum controllers are present (all versions are affected)
Your environment is affected if you have a Modicon M580 with firmware below 2.90, M340 below 3.10, or any Premium or Quantum model, where reading invalid data can trigger an unhandled exception and cause denial of service.
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
Apply the available firmware updates (V2.90+ for M580, V3.10+ for M340) and review compensating controls for Premium and Quantum. Since firmware updates require maintenance windows in production OT environments, plan updates carefully and validate system operation post-update.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-6809 — 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-2019-6809 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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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.
- 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
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