CVE-2021-20601
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 · uneditedImproper input validation vulnerability in GOT2000 series GT27 model all versions, GOT2000 series GT25 model all versions, GOT2000 series GT23 model all versions, GOT2000 series GT21 model all versions, GOT SIMPLE series GS21 model all versions, and GT SoftGOT2000 all versions allows an remote unauthenticated attacker to write a value that exceeds the configured input range limit by sending a malicious packet to rewrite the device value. As a result, the system operation may be affected, such as malfunction.
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 confidenceImproper input validation vulnerability in Mitsubishi Electric GOT2000 series HMI devices (GT27, GT25, GT23, GT21), GOT SIMPLE series (GS21), and GT SoftGOT2000 allows remote unauthenticated attackers to send malicious packets that write device values exceeding configured input range limits, potentially causing system malfunction.
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
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 the HMI device modelLocate the model label on the physical HMI device or check the device configuration in GT Designer3/GT Works3 software. Common locations are the front panel label or system information in the software.Affected if The model number matches GT2104, GT2103 (any variant), GS2110, GS2107, or is part of the GT27, GT25, GT23, GT21, GS21, or GT SoftGOT2000 series.
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Confirm the device runs GT SoftGOT2000 softwareCheck if GT SoftGOT2000 is installed on a PC or server by reviewing installed programs in the operating system or checking for the software in the program files directory.Affected if GT SoftGOT2000 software is installed and running, regardless of version.
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Verify network exposure of the HMI deviceReview network firewall rules, VLAN configurations, and device IP addressing to determine if the HMI device is accessible from untrusted networks or the internet.Affected if The HMI device has a routable IP address and is reachable from networks outside the trusted operational technology network.
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Check for input range limit configurationsOpen the GT Designer3 project file and review the device/dataserver settings, particularly the configured limits for numeric input fields or device value ranges.Affected if No input range limits are configured for device value writes, or limits are set but not enforced by the device firmware.
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Review GT Designer3 project security settingsExamine the security settings in the GT Designer3 project file for authentication requirements and access control lists related to device write operations.Affected if Remote unauthenticated write operations are permitted or no authentication is required for device value modifications.
You are affected if your HMI device is any of the specific models listed (GT2104, GT2103 variants, GS2110, GS2107) or runs GT SoftGOT2000, and the device is network-accessible to untrusted parties.
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 dataApply vendor-supplied firmware updates for all affected HMI models and implement network segmentation/firewall controls to restrict untrusted network access to these devices.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA5.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,216.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20601 — 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-2021-20601 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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