CVE-2021-20708
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 · uneditedNEC Aterm devices (Aterm WF1200CR firmware Ver1.3.2 and earlier, Aterm WG1200CR firmware Ver1.3.3 and earlier, and Aterm WG2600HS firmware Ver1.5.1 and earlier) allow authenticated attackers to execute arbitrary OS commands by sending a specially crafted request to a specific URL.
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 confidenceCommand injection vulnerability in NEC Aterm routers (WF1200CR, WG1200CR, WG2600HS) allows authenticated attackers to execute arbitrary OS commands via a specially crafted request to a specific URL endpoint. The vulnerability exists in specific firmware versions and requires authentication but can lead to complete device compromise.
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<= 1.3.2<= 1.3.3<= 1.5.1CVSS 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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/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 exact Aterm router modelCheck the device label on the router itself or log into the web admin interface (typically http://192.168.0.1 or http://192.168.1.1) and locate the model number displayed in the status or device information pageAffected if The model is WF1200CR, WG1200CR, or WG2600HS
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Check the installed firmware versionIn the router web admin interface, navigate to the firmware or system information page and note the exact firmware version number displayedAffected if The firmware version is 1.3.2 or lower for WF1200CR, 1.3.3 or lower for WG1200CR, or 1.5.1 or lower for WG2600HS
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Verify remote administrative access is enabledIn the router web admin interface, check the remote management settings (often under Advanced, Administration, or Security settings) to determine if the web interface is accessible from WAN/outside networksAffected if Remote web management is enabled and the router is directly accessible from the internet
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Confirm authentication is required for the admin interfaceAttempt to access the router login page from both LAN and WAN perspectives to verify that authentication is enforcedAffected if The admin interface is accessible without authentication or uses default/weak credentials
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Inspect for suspicious command execution indicatorsReview any available system logs, command logs, or traffic logs on the router for unexpected or encoded commands sent to the web interface, particularly to endpoints under /cgi-bin/ or similar administrative pathsAffected if Unusual or unexpected commands appear in logs, or the specific vulnerable endpoint is accessible and responds to crafted requests
You are affected if you own a WF1200CR, WG1200CR, or WG2600HS router with firmware at or below the affected version AND the router admin interface is accessible to untrusted networks.
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 affected Aterm devices to the latest firmware versions (WF1200CR >Ver1.3.2, WG1200CR >Ver1.3.3, WG2600HS >Ver1.5.1). Additionally, restrict administrative access to trusted networks and use strong credentials to limit attack surface.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20708 — 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-2021-20708 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