CVE-2020-5802
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 attacker-controlled memory allocation size can be passed to the C++ new operator in RnaDaSvr.dll by sending a specially crafted ConfigureItems message to TCP port 4241. This will cause an unhandled exception, resulting in termination of RSLinxNG.exe. Observed in FactoryTalk 6.11. All versions of FactoryTalk Linx are affected.
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 memory allocation vulnerability exists in FactoryTalk Linx (RSLinxNG.exe) where an attacker can send a specially crafted ConfigureItems message to TCP port 4241 containing an attacker-controlled size value passed to the C++ new operator. This causes an unhandled exception resulting in denial of service via process termination.
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<= 6.11CVSS 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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Verify FactoryTalk Linx installationLook for RSLinxNG.exe on the system, typically in C:\Program Files\Rockwell Software\FactoryTalk Linx\ or check Windows Programs and Features for FactoryTalk Linx entryAffected if FactoryTalk Linx is installed and RSLinxNG.exe is present
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Check installed versionRight-click RSLinxNG.exe in the installation directory, select Properties, then Details to view the File Version, or check the version listed in Add/Remove ProgramsAffected if The version number is 6.11 or lower (the CVE specifies <= 6.11 is affected)
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Verify TCP port 4241 is listeningOpen Command Prompt and run 'netstat -an | findstr 4241' to check if the service is listening on TCP port 4241Affected if Port 4241 shows LISTENING state, indicating the service is exposed on the network
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Confirm service is runningOpen Services.msc and look for FactoryTalk Linx service, or run 'tasklist | findstr RSLinxNG' to check if the process is activeAffected if The RSLinxNG.exe process is running, creating an active attack surface
The system is affected if FactoryTalk Linx version 6.11 or lower is installed with TCP port 4241 open and the RSLinxNG service actively running and accessible over the network.
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 dataRestrict network access to TCP port 4241 to trusted IPs only via firewall or network segmentation. Apply vendor patches when released. Consider upgrading to newer versions if available.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-5802 — 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-2020-5802 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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