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Dap 1880ac FirmwareOperating system · Dlink

CVE-2021-20696

HIGH · 8.8 CVSS v3.1 Published 2021-04-26
Fix available
A fix is available. Upgrade to after 1.21 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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
DAP-1880AC firmware version 1.21 and earlier allows a remote authenticated attacker to execute arbitrary OS commands by sending a specially crafted request to a specific CGI program.

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

OS command injection vulnerability in DAP-1880AC access point firmware where an authenticated remote attacker can send specially crafted requests to a specific CGI program to execute arbitrary operating system commands. This is a classic command injection flaw (CWE-78) in the web interface's input validation.

MitigationUpgrade DAP-1880AC firmware to a version newer than 1.21. If immediate patching is not possible, restrict network access to the device's management interface to trusted IPs only and consider disabling CGI endpoints if exposed to untrusted networks.

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
Dap 1880ac FirmwareOperating system
Affected:<= 1.21

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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

  1. Identify the device model
    Access the device's web interface or check the physical device label to confirm the model is D-Link DAP-1880AC. You can also check via SSH or console if available, using 'cat /proc/cpuinfo' or checking boot logs for model identification.
    Affected if The device is a D-Link DAP-1880AC access point.
  2. Check the installed firmware version
    Log into the device's web interface and navigate to the Status or System Information page to view the firmware version. Alternatively, access via SSH or console and run 'cat /proc/version' or check /etc/version file if accessible.
    Affected if The firmware version is 1.21 or lower.
  3. Verify the web management interface is enabled
    Check the device configuration for web interface settings. Look for HTTP/HTTPS management access settings in the web GUI under Administration or System settings. Confirm if the web interface is listening on ports 80 or 443.
    Affected if The web interface is enabled and accessible on the network.
  4. Confirm CGI functionality is active
    Inspect the device's HTTP server configuration or attempt to access a known CGI endpoint (such as /cgi-bin/ with common D-Link paths). Check if the device responds to CGI requests.
    Affected if CGI program endpoints are accessible and responding.

You are affected if you are running D-Link DAP-1880AC firmware version 1.21 or lower with the web interface and CGI functionality enabled and accessible on your network.

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 1.21
Interim mitigation

Upgrade DAP-1880AC firmware to a version newer than 1.21. If immediate patching is not possible, restrict network access to the device's management interface to trusted IPs only and consider disabling CGI endpoints if exposed to untrusted networks.

Recommended fix Moderate confidence

Latest available firmware version from D-Link Japan (must be >1.21)

  1. 1. Check D-Link Japan's official support page (www.dlink-jp.com) for the latest firmware version for DAP-1880AC
  2. 2. Download the firmware update that addresses CVE-2021-20696
  3. 3. Access the DAP-1880AC web management interface
  4. 4. Navigate to the firmware upgrade section
  5. 5. Upload and apply the patched firmware version
Caveat Before upgrading, backup current configuration and review release notes for any feature changes or migration requirements

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

Fix this in Dap 1880ac Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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-2021-20696 in production — separate from our analysis above.

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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