CVE-2019-6820
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-306: Missing Authentication for Critical Function vulnerability exists which could cause a modification of device IP configuration (IP address, network mask and gateway IP address) when a specific Ethernet frame is received in all versions of: Modicon M100, Modicon M200, Modicon M221, ATV IMC drive controller, Modicon M241, Modicon M251, Modicon M258, Modicon LMC058, Modicon LMC078, PacDrive Eco ,PacDrive Pro, PacDrive Pro2
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 confidenceThis vulnerability allows unauthenticated modification of network configuration (IP address, subnet mask, gateway) on affected Schneider Electric Modicon and PacDrive controllers via specially crafted Ethernet frames. The lack of authentication for this critical network configuration function enables an attacker to disrupt device communication or potentially redirect network traffic by changing the IP settings without any credentials.
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 dataall versionsall versionsall versionsall versionsall versionsall versionsall 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
- Low
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 affected Schneider Electric controllers in your environmentInventory your industrial control devices and verify if any of the following models are present: Modicon M100, M200, M221, M241, M251, M258, LMC058, or ATV IMC Drive Controller. Check device nameplates, asset inventories, or network scans for these model numbers.Affected if Any of these specific Schneider Electric controller models are present on the network
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Verify network management interface exposureDetermine if the affected controllers have their Ethernet management interfaces enabled and accessible on the network segment where untrusted devices could send Ethernet frames. Check network diagrams and access control lists.Affected if The controller Ethernet interfaces are reachable from network segments with untrusted or unauthorized devices
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Check for unauthenticated network configuration capabilityExamine whether the device network configuration functions (IP address, subnet mask, gateway settings) can be modified through Ethernet-based protocols without requiring authentication credentials.Affected if Network configuration parameters can be changed via Ethernet frames without authentication
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Monitor for configuration change network trafficUse a network sniffer or IDS to capture and inspect Ethernet traffic destined for the controller IP address on ports typically used for network management. Look for anomalous or unexpected configuration change packets.Affected if Unauthenticated or unexpected network configuration packets are observed targeting the controller
You are affected if any of the listed Schneider Electric Modicon or ATV IMC controllers are present on a network where untrusted Ethernet frames can reach the device's management interface without authentication controls preventing unauthorized network configuration changes.
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 dataImplement network segmentation and firewall rules to restrict unauthorized Ethernet traffic to industrial control devices. Apply vendor-supplied firmware patches when available and monitor network traffic for anomalous configuration change requests.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA6.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-6820 — 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-2019-6820 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
- No weaponised exploit code, or anything meant to cause harm
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