CVE-2020-6985
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 · uneditedIn Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, these devices use a hard-coded service code for access to the console.
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 confidenceMoxa PT-7528 (firmware v4.0 or lower) and PT-7828 (firmware v3.9 or lower) industrial ethernet switches contain a hard-coded service code that provides unauthenticated console access. This backdoor credentials vulnerability allows any attacker with network access to the device to bypass authentication and gain full administrative console control.
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<= 4.0<= 4.0<= 4.0<= 4.0<= 4.0<= 4.0<= 4.0<= 4.0CVSS 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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Identify Moxa PT-7528 or PT-7828 devices on the networkReview network inventory or use network scanning tools to discover Moxa industrial ethernet switches. Check device model numbers and serial numbers through management interfaces or physical inspection.Affected if Any PT-7528 or PT-7828 switch is found on the network
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Determine the firmware versionAccess the device console, web interface, or management software and navigate to the system information or firmware version section. Compare the installed version against the affected ranges: PT-7528 firmware <= 4.0, PT-7828 firmware <= 3.9.Affected if The device firmware version is at or below 4.0 for PT-7528, or at or below 3.9 for PT-7828
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Verify console or management service accessibilityCheck if Telnet, SSH, or serial console ports are enabled and reachable on the affected device. Attempt to access the device from a network location.Affected if Console, Telnet, or SSH services are exposed and accessible from the network
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Test for the hardcoded credentialsAttempt authentication using the hardcoded service code credentials referenced in the CVE. This allows unauthenticated console access without legitimate user credentials.Affected if Authentication succeeds using undocumented credentials, confirming the backdoor is present
A user is affected if they have a PT-7528 device running firmware <= 4.0 or PT-7828 device running firmware <= 3.9 with exposed management interfaces that can be accessed using the hardcoded credentials.
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 firmware to versions higher than 4.0 for PT-7528 and higher than 3.9 for PT-7828. Until patched, isolate affected devices behind firewalls and disable unnecessary management interfaces to reduce attack surface.
Moxa PT-7528 series firmware > 4.0 (contact Moxa for specific fixed release)
- 1. Identify all affected Moxa PT-7528 series devices on the network
- 2. Check the current firmware version of each device through the management interface
- 3. Obtain the latest firmware version from the official Moxa website or support portal
- 4. Follow Moxa's official firmware upgrade procedure documented in the device manual
- 5. After upgrading, change any default or hard-coded credentials to strong, unique passwords
- 6. Verify the upgrade was successful and the hard-coded credential vulnerability is resolved
- 7. Implement regular credential rotation policies to prevent future vulnerabilities
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation2.0 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-2020-6985 — 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-2020-6985 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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