CVE-2021-20168
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 · uneditedNetgear RAX43 version 1.0.3.96 does not have sufficient protections to the UART interface. A malicious actor with physical access to the device is able to connect to the UART port via a serial connection, login with default credentials, and execute commands as the root user. These default credentials are admin:admin.
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 confidenceThe Netgear RAX43 router firmware 1.0.3.96 lacks sufficient protections on its UART serial interface. A physically proximate attacker can connect to the exposed UART pins, access the serial console, authenticate using the default credentials (admin:admin), and execute commands as the root user.
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= 1.0.3.96CVSS 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
- Physical
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:P/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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Confirm device is Netgear RAX43Identify the router model via label on device or administrative web interfaceAffected if Device model is not Netgear RAX43
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Check firmware versionAccess router web interface, navigate to Administration > Firmware Update or check the label on the device for firmware version 1.0.3.96Affected if Firmware version equals 1.0.3.96
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Inspect UART pins for physical exposurePhysically examine the router circuit board for exposed UART pin headers (typically 4 pins labeled TX, RX, GND, VCC)Affected if UART pins are physically accessible and exposed on the circuit board
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Verify default credentials are in useAttempt to access UART console via serial connection (baud rate typically 115200 8N1) using default credentials admin:adminAffected if Default credentials admin:admin successfully authenticate on UART console
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Check UART console authentication requirementConnect to UART serial interface and observe if a password is required before shell access is grantedAffected if UART console provides root shell access without requiring any password or additional authentication
Environment is affected if you have a Netgear RAX43 router running firmware 1.0.3.96 with physically accessible UART pins that allow root shell access using default admin:admin credentials without additional authentication.
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 dataChange the default administrator credentials immediately and implement physical security controls to restrict access to the device's UART pins. If the device firmware supports it, disable the UART console or require additional authentication.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20168 — 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-2021-20168 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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- 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
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