CVE-2021-33023
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 heap-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 · moderate confidenceAdvantech WebAccess versions 9.02 and prior contain a heap-based buffer overflow vulnerability in the web interface component. This memory corruption flaw can be exploited remotely, potentially allowing an attacker to achieve arbitrary code execution on the affected system.
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 installationCheck for WebAccess installation directories or services on the system. Common installation paths on Windows include C:\Advantech\WebAccess or check Windows Services for a 'WebAccess' service entry.Affected if Advantech WebAccess software is present on the system
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Determine installed WebAccess versionLocate version information in the installation directory (often in an About dialog, version.txt, or readme file) or check Windows Programs and Features. The version format is X.X.X (for example, 9.0.2, 8.1.0).Affected if Installed version is 9.0.2 or any earlier version (any version <= 9.0.2)
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Verify web interface component is runningConfirm the WebAccess web service is active. Check Windows Services for the WebAccess service status, or verify the web server is listening on common ports (80, 443, or custom ports like 8080) associated with WebAccess.Affected if Web interface component is enabled and the service is running
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Check network exposure of web portsReview firewall rules and network configuration to identify if WebAccess HTTP/HTTPS ports are exposed to network segments outside the local system. Use netstat or port scanning tools to identify which interfaces the web service binds to.Affected if WebAccess web interface ports are accessible from untrusted or external networks
The environment is affected if Advantech WebAccess version 9.0.2 or earlier is installed with the web interface component enabled and network-accessible.
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.
dbcve · scopedUpgrade Advantech WebAccess to a version beyond 9.02 as soon as vendor patches become available. Until then, isolate affected systems on a restricted network segment and block external access to the WebAccess HTTP/HTTPS ports.
Advantech WebAccess version greater than 9.0.2 (contact vendor for exact fixed release)
- 1. Identify the current installed version of Advantech WebAccess
- 2. Contact Advantech technical support or visit their official download portal to obtain the latest version
- 3. Before upgrading, back up all WebAccess configurations, project files, and databases
- 4. Review upgrade documentation for any prerequisites or migration requirements
- 5. Stop all WebAccess services before performing the upgrade
- 6. Install the latest version of Advantech WebAccess (version greater than 9.0.2)
- 7. Restore configurations from the backup if needed
- 8. Restart WebAccess services and verify the application is functioning correctly
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-33023 — 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-2021-33023 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
- No spam, self-promotion, credentials, or personal data