CVE-2021-20697
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 · uneditedMissing authentication for critical function in DAP-1880AC firmware version 1.21 and earlier allows a remote attacker to login to the device as an authenticated user without the access privilege via unspecified vectors.
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 confidenceMissing authentication enforcement in DAP-1880AC firmware versions 1.21 and earlier allows a remote attacker to bypass login controls and gain authenticated access to the device without proper privileges. This is a critical authentication bypass vulnerability in a network device firmware.
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<= 1.21CVSS 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 the device modelLog into the device web interface or check the physical device label for the exact model number (DAP-1880AC)Affected if The device is not a DAP-1880AC unit
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Determine the installed firmware versionAccess the device web management interface, typically at http://[device IP], then navigate to the Status or System Information page to view the firmware version. Alternatively, check the administration or maintenance section for firmware information.Affected if The firmware version is 1.21 or earlier
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Verify management interface accessibilityConfirm the device web interface is reachable on the network by attempting to access http://[device IP] from a connected workstationAffected if The device management interface is exposed to untrusted networks (not behind a firewall or ACL)
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Check for unexpected authenticated sessionsReview the device for any active sessions or logged-in users that you do not recognize, or check system logs for successful logins from unknown IP addressesAffected if There are active sessions or logins from unknown sources after the device was not accessed by legitimate administrators
You are affected if the device is a D-Link DAP-1880AC running firmware version 1.21 or earlier and its management interface is accessible on the network.
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.
From vendor dataUpdate DAP-1880AC firmware to a version newer than 1.21. If immediate patching is not possible, isolate the device behind a firewall or restrict network access to prevent external exploitation.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20697 — 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-2021-20697 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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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.
- 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