CVE-2019-6521
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 · uneditedWebAccess/SCADA, Version 8.3. Specially crafted requests could allow a possible authentication bypass that could allow an attacker to obtain and manipulate sensitive information.
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 confidenceCVE-2019-6521 is an authentication bypass vulnerability in Advantech WebAccess/SCADA version 8.3. The vulnerability allows attackers to bypass authentication mechanisms through specially crafted HTTP requests, enabling unauthorized access to sensitive operational data and the ability to manipulate system information.
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= 8.3CVSS 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
- Low
- Availability
- Low
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
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/SCADA installationLocate the WebAccess installation directory or check system services for Advantech WebAccess/SCADA processes. Common installation paths include C:\Program Files\Advantech\WebAccess or C:\inetpub\wwwroot\WebAccess.Affected if The software is installed on the system
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Verify installed version is 8.3Check the product version through the web interface login page, the Windows Programs and Features control panel, or the version.dll/version.txt file within the WebAccess installation directory. Compare against the affected version = 8.3.Affected if The installed version is exactly 8.3
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Determine web interface exposureCheck network configuration to see if the WebAccess/SCADA web server (typically ports 80/443 or custom ports like 8080) is accessible from network segments outside the operational technology (OT) network.Affected if The SCADA web interface is reachable from untrusted networks or the internet
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Inspect HTTP traffic logs for authentication bypass attemptsReview WebAccess IIS or Apache logs, typically found in the installation logs folder, for unusual HTTP requests that may indicate authentication bypass exploitation patterns such as malformed authentication headers or unexpected request paths.Affected if Suspicious HTTP requests targeting authentication mechanisms are present in the logs
The environment is affected only if Advantech WebAccess/SCADA version 8.3 is installed and its web interface is accessible, enabling attackers to send specially crafted HTTP requests to bypass authentication.
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 available vendor patches for WebAccess/SCADA 8.3 or upgrade to a patched version. If patching is not immediately feasible, implement network segmentation and additional access controls to limit exposure to the SCADA interface.
- Consultation3.0 h
- Implementation6.0 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-2019-6521 — 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-2019-6521 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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