CVE-2021-38389
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 · uneditedAdvantech WebAccess versions 9.02 and prior are vulnerable to a stack-based buffer overflow, which may allow an attacker to remotely execute code.
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 confidenceAdvantech WebAccess versions 9.02 and prior contain a stack-based buffer overflow vulnerability that allows remote attackers to execute arbitrary code by overflowing a stack-allocated buffer, likely through crafted network requests to the web interface.
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<= 9.0.2CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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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Confirm Advantech WebAccess is installedCheck for the presence of Advantech WebAccess installation directories (commonly under C:\Advantech\WebAccess or similar paths) or look for a service named 'WebAccess' in Windows Services.Affected if The software is found installed on the system.
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Determine installed WebAccess versionLocate version information in the installation directory, typically in an About or Version file, or right-click the main executable and view Properties > Details for the File Version.Affected if The installed version is 9.02 or any version lower (such as 9.01, 8.x, etc.).
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Identify if the web interface service is runningCheck if the WebAccess service is running via Windows Services console (services.msc) or by running 'sc query WebAccess' at command prompt.Affected if The web interface service is actively running and listening on network ports.
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Verify network exposure of the web interfaceRun 'netstat -an' or use a port scanner to identify which ports the WebAccess HTTP/HTTPS service is listening on, then determine if those ports are accessible from untrusted networks.Affected if The web interface ports (typically 80, 443, or custom ports) are bound to external-facing network interfaces or accessible beyond the local subnet.
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Inspect web access configurationExamine the WebAccess configuration files or management console to confirm whether the web interface is enabled and accessible.Affected if The web interface feature is enabled and configured to accept remote connections.
A user is affected if Advantech WebAccess version 9.02 or prior is installed with the web interface service running and exposed to network access.
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 dataUpdate Advantech WebAccess to a patched version newer than 9.02. If patching is not immediately possible, restrict network access to the WebAccess interface and implement compensating controls such as network segmentation.
- Consultation8.0 h
- Implementation16.0 h
- Testing24.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $15,232.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-38389 — 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-2021-38389 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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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