CVE-2020-27274
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 · uneditedSome parsing functions in the affected product do not check the return value of malloc and the thread handling the message is forced to close, which may lead to a denial-of-service condition on the OPC UA Tunneller (versions prior to 6.3.0.8233).
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 confidenceThe OPC UA Tunneller contains parsing functions that fail to check the return value of malloc() calls. When memory allocation fails and returns NULL, the unhandled error causes the message-handling thread to terminate, resulting in a denial-of-service condition.
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< 6.3.0.8233CVSS 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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Locate OPC UA Tunneller installationCheck for the Honeywell OPC UA Tunneller service or executable on the system. Common locations include C:\Program Files\Honeywell\OPC UA Tunneller\ or review installed programs in Windows Control Panel.Affected if The software is present on the system
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Determine installed versionRight-click the tunneller executable (typically named something like OpcUaTunneller.exe or similar) and select Properties, then check the Details tab for the File Version. Alternatively, check the Windows service properties if installed as a service.Affected if The version displayed is lower than 6.3.0.8233
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Verify the tunneller service is runningOpen Windows Services (services.msc) and confirm the OPC UA Tunneller service status. Also check if the process is active in Task Manager.Affected if The service is running and actively handling OPC UA messages
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Confirm message parsing is in useReview the tunneller configuration to verify it is configured to accept and process OPC UA client connections. Check config files for active listener ports or endpoints.Affected if The tunneller is configured with active endpoints accepting connections
A user is affected if Honeywell OPC UA Tunneller version is installed and running with a version number lower than 6.3.0.8233.
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 data6.3.0.8233
Upgrade OPC UA Tunneller to version 6.3.0.8233 or later, which includes proper malloc return value validation in the parsing functions.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-27274 — 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-2020-27274 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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