dbcve.org
Nbg6816 FirmwareOperating system · Zyxel

CVE-2021-4030

HIGH · 8.8 CVSS v3.1 Published 2022-02-24
Fix available
A fix is available. Upgrade to 1.00 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

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
A cross-site request forgery vulnerability in the HTTP daemon of the Zyxel ARMOR Z1/Z2 firmware could allow an attacker to execute arbitrary commands if they coerce or trick a local user to visit a compromised website with malicious scripts.

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 confidence

A cross-site request forgery (CSRF) vulnerability in the HTTP daemon of Zyxel ARMOR Z1/Z2 firmware allows remote attackers to execute arbitrary commands by tricking an authenticated user into visiting a malicious website that sends crafted requests to the vulnerable device.

MitigationApply available firmware updates from Zyxel; if no update exists, disable remote HTTP management interfaces and restrict administrative access to trusted networks to reduce the attack surface.

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
Nbg6816 FirmwareOperating system
Affected:= 1.00\(aawb.10\)c0
Nbg6817 FirmwareOperating system
Affected:< 1.00\(abcs.11\)c0

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 checks

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

  1. Identify the device model
    Check the device label or web interface for the model number (NBG6816 or NBG6817)
    Affected if Device is not an NBG6816 or NBG6817 model (not affected)
  2. Determine the firmware version
    Access the device web interface (usually at 192.168.1.1) and navigate to System > Firmware or Status page to view the installed firmware version
    Affected if Firmware version equals 1.00(aawb.10)c0 (NBG6816) or is lower than 1.00(abcs.11)c0 (NBG6817)
  3. Verify HTTP management interface is enabled
    In the device web interface, check Network > Remote Management or Administration > HTTP Access settings to confirm the HTTP daemon is enabled
    Affected if HTTP management interface is enabled on the device
  4. Confirm remote HTTP access is permitted
    Check the remote access settings in the web interface under Network > Remote Management or similar; determine if HTTP is accessible from WAN/outside networks
    Affected if Remote HTTP management access is permitted to untrusted networks

Device is affected if it is an NBG6816 running firmware 1.00(aawb.10)c0 or an NBG6817 running firmware below 1.00(abcs.11)c0, and the HTTP management interface 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 1.00 or later
Fixed in 1.00
Interim mitigation

Apply available firmware updates from Zyxel; if no update exists, disable remote HTTP management interfaces and restrict administrative access to trusted networks to reduce the attack surface.

Recommended fix Moderate confidence

Zyxel ARMOR Z1/Z2 firmware 1.00(abcs.11)c0 or later for NBG6817; subsequent release for NBG6816

  1. 1. Identify the exact model number (NBG6816 or NBG6817) of the Zyxel ARMOR device
  2. 2. Navigate to the official Zyxel support website (www.zyxel.com)
  3. 3. Locate the firmware download section for the specific ARMOR model
  4. 4. Download firmware version 1.00(abcs.11)c0 or later for NBG6817; for NBG6816, download the version subsequent to 1.00(aawb.10)c0
  5. 5. Access the device web management interface
  6. 6. Navigate to the Administration or Firmware Upgrade section
  7. 7. Upload and apply the downloaded firmware file
  8. 8. Wait for the device to reboot and verify the firmware version was applied successfully
Caveat Firmware upgrades may reset some configurations; back up current settings before upgrading if possible

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

Fix this in Nbg6816 Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-4030 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-4030 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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