CVE-2023-37926
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 · uneditedA buffer overflow vulnerability in the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, and VPN series firmware versions 4.30 through 5.37, could allow an authenticated local attacker to cause denial-of-service (DoS) conditions by executing the CLI command to dump system logs on an affected device.
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 confidenceA buffer overflow vulnerability exists in the CLI command functionality for dumping system logs on multiple Zyxel firewall series (ATP, USG FLEX, USG FLEX 50W, USG20W-VPN, and VPN). An authenticated local attacker with CLI access can trigger the vulnerability by executing the log dump command, causing a buffer overflow that results in denial of service.
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>= 4.32, <= 5.37>= 4.50, <= 5.37>= 4.16, <= 5.37>= 4.30, <= 5.37CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 modelAccess the CLI or web interface and retrieve the exact model name (ATP, USG FLEX, USG FLEX 50W, USG20W-VPN, or VPN series)Affected if The model is one of ATP, USG FLEX, USG FLEX 50W, USG20W-VPN, or VPN series
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Check the firmware versionIn CLI, run 'show system-info' or in the web interface go to Maintenance > Firmware to view the current ZLD firmware versionAffected if The firmware version is greater than or equal to the lower bound (4.16, 4.30, 4.32, or 4.50 depending on model) AND less than or equal to 5.37
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Verify CLI access is enabledIn the web interface, go to Security > Admin Access > CLI or check if SSH/Telnet access to the device is allowedAffected if CLI access (SSH or console) is enabled and reachable on the device
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Confirm the log dump command existsIn CLI, attempt to access the log dump functionality, typically via commands like 'show log' or a dedicated log dump command in diagnostic modeAffected if The device supports the log dump CLI command that can be executed by an authenticated user
The device is affected if it is an ATP, USG FLEX, USG FLEX 50W, USG20W-VPN, or VPN model running firmware version 5.37 or lower, with CLI access enabled and the log dump command available to authenticated users.
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 dataApply the vendor-supplied firmware update to a version beyond 5.37 for all affected product series. Until patched, limit CLI access to trusted personnel only and monitor for abnormal device behavior.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-37926 — 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-2023-37926 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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