CVE-2021-40873
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 · uneditedAn issue was discovered in Softing Industrial Automation OPC UA C++ SDK before 5.66, and uaToolkit Embedded before 1.40. Remote attackers to cause a denial of service (DoS) by sending crafted messages to a client or server. The server process may crash unexpectedly because of a double free, and must be restarted.
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 confidenceA double free vulnerability exists in Softing Industrial Automation OPC UA C++ SDK before version 5.66 and uaToolkit Embedded before version 1.40. Remote attackers can send crafted OPC UA messages to trigger memory corruption, causing the server or client process to crash unexpectedly and require 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< 5.18<= 2.31< 5.66<= 1.22>= 3.5< 1.73< 1.40CVSS 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 installed Softing OPC UA productsReview installed software or check product directories for Softing Industrial Automation products such as Datafeed Opc Suite, Edgeconnector, Secure Integration Server, Th Scope, Uagates, or Uatoolkit EmbeddedAffected if Any Softing product from the affected list is installed
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Check Softing Datafeed Opc Suite versionLocate the Datafeed Opc Suite installation and retrieve its version number (typically found in the application, About section, or version file)Affected if Version is less than 5.18
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Check Softing Edgeconnector versionLocate the Edgeconnector installation and retrieve its version numberAffected if Version is 2.31 or lower
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Check Softing Secure Integration Server versionLocate the Secure Integration Server installation and retrieve its version numberAffected if Version is 1.22 or lower
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Check Softing Uagates versionLocate the Uagates installation and retrieve its version numberAffected if Version is less than 1.73
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Check Softing Uatoolkit Embedded versionIf using the uaToolkit Embedded SDK in a custom application, check the SDK version referenced in the project or installed library filesAffected if Version is less than 1.40 or the underlying C++ SDK version is less than 5.66
The environment is affected if any Softing product from the listed affected versions is installed and the OPC UA server or client functionality is in use.
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 data1.401.735.18
Upgrade Softing OPC UA C++ SDK to version 5.66 or later, and uaToolkit Embedded to version 1.40 or later, to remediate the double free vulnerability. Validate the update in a staging environment before production deployment.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-40873 — 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-2021-40873 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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