CVE-2023-22913
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 post-authentication command injection vulnerability in the “account_operator.cgi” CGI program of Zyxel USG FLEX series firmware versions 4.50 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow a remote authenticated attacker to modify device configuration data, resulting in denial-of-service (DoS) conditions 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 command injection vulnerability exists in the account_operator.cgi CGI program of Zyxel USG FLEX and VPN series firewalls. The flaw allows authenticated remote attackers to inject arbitrary commands through the CGI program, enabling modification of device configuration and potential 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>= 4.50, <= 5.35>= 4.50, <= 5.35>= 4.50, <= 5.35>= 4.50, <= 5.35>= 4.50, <= 5.35>= 4.50, <= 5.35>= 4.50, <= 5.35>= 4.50, <= 5.35CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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 modelAccess the device web interface or use CLI command 'show system-info' to confirm the exact model number matches one of: USG Flex 100, USG Flex 100w, USG Flex 200, USG Flex 50, USG Flex 50w, USG Flex 500, USG Flex 700, or VPN100Affected if The model is any of the listed affected models and falls within the firmware range
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Check the installed firmware versionIn the web interface go to Maintenance > Firmware or use CLI command 'show version' to retrieve the firmware version numberAffected if The firmware version is >= 4.50 and <= 5.35
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Verify account_operator.cgi accessibilityConfirm the CGI program account_operator.cgi exists on the device by attempting to access it via the web interface or checking the /web/cgi/ directory via CLI if accessibleAffected if The account_operator.cgi program is present and reachable over the network
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Check if remote administrative access is enabledIn the web interface go to Network > Remote Management or use CLI command 'show admin-user' to see if remote administrative access is permittedAffected if Remote administrative access to the device is enabled and the CGI is externally reachable
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Confirm authentication methodsReview the list of admin accounts and authentication settings in the device to determine if unauthenticated or weakly authenticated access is possibleAffected if An attacker with valid credentials can access the account_operator.cgi CGI program
The device is affected if it is any of the listed models running firmware version 4.50 through 5.35, has the account_operator.cgi accessible, and permits remote administrative access.
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.
dbcve · scopedApply vendor-supplied firmware patches to address this vulnerability; until patched, limit administrative access to trusted users only and monitor for unauthorized configuration changes.
Zyxel USG FLEX/VPN series firmware version 5.36 or later
- 1. Identify the exact model number (e.g., USG Flex 100, USG Flex 50, VPN100) from the affected device.
- 2. Navigate to Zyxel's support website at www.zyxel.com and locate the firmware download section.
- 3. Search for the specific model and check available firmware versions.
- 4. Download firmware version 5.36 or later (verify this is the version that addresses CVE-2023-22913).
- 5. Review the firmware release notes to confirm the security fix for CVE-2023-22913 is included.
- 6. Back up the current device configuration before upgrading.
- 7. Upload and install the new firmware via the device's web management interface or CLI.
- 8. After upgrade, verify the device is functioning correctly and the vulnerability is remediated.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation6.0 h
- Testing8.0 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 $5,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-22913 — 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-2023-22913 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
- No spam, self-promotion, credentials, or personal data