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Mgate Mb3180 FirmwareOperating system · Moxa

CVE-2021-4161

HIGH · 7.5 CVSS v3.1 Published 2021-12-27
Fix available
A fix is available. Upgrade to after 4.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
The affected products contain vulnerable firmware, which could allow an attacker to sniff the traffic and decrypt login credential details. This could give an attacker admin rights through the HTTP web server.

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 confidence

The vulnerability exists in firmware of affected products, allowing an attacker to perform network traffic sniffing and decrypt login credentials. This credential theft enables unauthorized admin access to the HTTP web server.

MitigationApply vendor-supplied firmware updates when available; until then, network segmentation and monitoring for suspicious traffic sniffing activities are recommended.

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
Mgate Mb3180 FirmwareOperating system
Affected:<= 2.2
Mgate Mb3280 FirmwareOperating system
Affected:<= 4.1
Mgate Mb3480 FirmwareOperating system
Affected:<= 3.2

CVSS 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
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Moxa Mgate model number
    Locate the physical device label or access the device's web interface to confirm the exact model (Mb3180, Mb3280, or Mb3480)
    Affected if The device is one of the three affected models
  2. Check the installed firmware version
    Access the device's web interface (typically via HTTP) and navigate to the System Settings or Administration section to view the current firmware version, or use the device's console/cli if available
    Affected if The firmware version matches or is lower than 2.2 for Mb3180, 4.1 for Mb3280, or 3.2 for Mb3480
  3. Verify the HTTP web server is enabled
    Check the device configuration for HTTP web server settings; confirm the web interface is accessible by attempting to reach the device IP via HTTP in a browser
    Affected if The HTTP web server is enabled and reachable on the network
  4. Review network exposure of the management interface
    Check if the device HTTP interface is exposed to untrusted networks or the internet; review network firewall rules and VLAN configuration surrounding the device
    Affected if The HTTP web interface is accessible from untrusted or external networks

A user is affected if they have a Mb3180, Mb3280, or Mb3480 device running firmware at or below the specified version limits AND the HTTP web server is enabled and accessible.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to a release after 4.1
Interim mitigation

Apply vendor-supplied firmware updates when available; until then, network segmentation and monitoring for suspicious traffic sniffing activities are recommended.

Recommended fix Moderate confidence

Contact Moxa for latest firmware (versions higher than 2.2 for MB3180, higher than 4.1 for MB3280, higher than 3.2 for MB3480)

  1. 1. Contact Moxa technical support to obtain the latest firmware version for your specific Mgate model (MB3180, MB3280, or MB3480)
  2. 2. Download the firmware update from Moxa's official support portal or obtained through technical support
  3. 3. Review the firmware release notes to confirm the update addresses CVE-2021-4161 and the cleartext transmission vulnerability
  4. 4. Backup current device configuration before applying firmware update
  5. 5. Apply the firmware upgrade following Moxa's documented upgrade procedure
  6. 6. After upgrade, verify that web interface is accessible only over HTTPS and that HTTP traffic is no longer accepted or automatically redirects to HTTPS
  7. 7. Change admin credentials after upgrade as a precautionary measure since they may have been compromised
Caveat Firmware upgrades may reset configuration; backup before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Mgate Mb3180 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-4161 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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