CVE-2023-40039
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 · uneditedAn issue was discovered on ARRIS TG852G, TG862G, and TG1672G devices. A remote attacker (in proximity to a Wi-Fi network) can derive the default WPA2-PSK value by observing a beacon frame.
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 confidenceARRIS TG852G, TG862G, and TG1672G devices ship with a default WPA2-PSK that can be derived by an attacker in Wi-Fi proximity simply by passively observing beacon frames. The beacon frame contains predictable or calculable information that reveals the default pre-shared key, allowing full Wi-Fi network compromise without authentication.
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 dataall versionsall versionsall versionsCVSS 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 router web interface or check the device label to confirm the exact model number (TG852G, TG862G, or TG1672G)Affected if The model is one of TG852G, TG862G, or TG1672G with any firmware version
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Verify current WPA2-PSK configurationLog into the router admin interface and navigate to Wi-Fi security settings. Record the currently configured WPA2-PSK/pre-shared keyAffected if The PSK has not been changed from the factory default
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Check if default PSK matches known patternsCompare the configured PSK against any documentation, stickers, or known default PSK patterns for these specific Arris models. If the PSK appears on the device label or in default configuration guides, it is likely the defaultAffected if The active PSK matches the factory default value or appears on the device label/packaging
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Capture and inspect beacon framesUse a wireless monitoring tool such as airodump-ng, Kismet, or Wireshark in monitor mode to capture Wi-Fi beacon frames from the network. Examine the beacon frame contents for any predictable data patterns or information that could reveal the PSKAffected if Beacon frames contain predictable or calculable information that reveals the default PSK without authentication
The defender is affected if they use an Arris TG852G, TG862G, or TG1672G device and have not changed the default WPA2-PSK from the factory value, as the default PSK can be derived by an attacker passively observing beacon frames.
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 dataImmediately change the default WPA2-PSK on affected devices to a strong, unique random PSK. If the device does not support custom PSK configuration or firmware updates addressing this weakness are unavailable, replace the device with a supported model.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-40039 — 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-2023-40039 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
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