dbcve.org
Vpn100 FirmwareOperating system · Zyxel

CVE-2022-0734

MEDIUM · 6.1 CVSS v3.1 Published 2022-05-24
Fix available
A fix is available. Upgrade to after 5.20 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 · unedited
A cross-site scripting vulnerability was identified in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.35 through 4.70, USG FLEX series firmware versions 4.50 through 5.20, ATP series firmware versions 4.35 through 5.20, and VPN series firmware versions 4.35 through 5.20, that could allow an attacker to obtain some information stored in the user's browser, such as cookies or session tokens, via a malicious script.

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 confidence

A stored cross-site scripting (XSS) vulnerability in the CGI program of multiple Zyxel firewall series (USG/ZyWALL, USG FLEX, ATP, VPN) allows attackers to inject malicious JavaScript that executes in victims' browsers, enabling theft of cookies, session tokens, or other browser-stored sensitive information.

MitigationUpgrade affected Zyxel devices to patched firmware versions beyond 4.70 (USG/ZyWALL), 5.20 (USG FLEX), or 5.20 (ATP/VPN) as specified in Zyxel security advisories.

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
Vpn100 FirmwareOperating system
Affected:>= 4.35, <= 5.20
Vpn1000 FirmwareOperating system
Affected:>= 4.35, <= 5.20
Vpn300 FirmwareOperating system
Affected:>= 4.35, <= 5.20
Vpn50 FirmwareOperating system
Affected:>= 4.35, <= 5.20
Atp100 FirmwareOperating system
Affected:>= 4.35, <= 5.20
Atp100w FirmwareOperating system
Affected:>= 4.35, <= 5.20
Atp200 FirmwareOperating system
Affected:>= 4.35, <= 5.20
Atp500 FirmwareOperating system
Affected:>= 4.35, <= 5.20

CVSS 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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Zyxel device model
    Access the device web management interface and locate the model name in the dashboard or system info page, or run 'show system-info' via CLI/SSH
    Affected if Device model is one of: Vpn50, Vpn100, Vpn300, Vpn1000, Atp100, Atp100w, Atp200, or Atp500
  2. Determine the installed firmware version
    In the web interface, go to Maintenance > Firmware or System > Firmware to view the current version. Alternatively, run 'show version' or 'show system-info' via CLI/SSH
    Affected if Firmware version is 4.35 through 5.20 inclusive (versions >= 4.35 and <= 5.20)
  3. Verify the CGI web interface is enabled
    Confirm the device has the web-based management interface (HTTP/HTTPS) enabled by checking the administration settings or by attempting to access the device login page
    Affected if The CGI/web management interface is accessible and the device is within the affected firmware range

The device is affected if it is a listed model (Vpn50/100/300/1000 or Atp100/100w/200/500) running firmware version 4.35 through 5.20, as this range contains the vulnerable CGI program.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to a release after 5.20
Interim mitigation

Upgrade affected Zyxel devices to patched firmware versions beyond 4.70 (USG/ZyWALL), 5.20 (USG FLEX), or 5.20 (ATP/VPN) as specified in Zyxel security advisories.

Recommended fix Moderate confidence

Firmware version > 5.20 (ATP and VPN series) - consult Zyxel support for exact fixed release

  1. 1. Identify the specific device model (ATP100, ATP100w, ATP200, ATP500, VPN50, VPN100, VPN300, or VPN1000) from the affected list
  2. 2. Access the device admin interface or Zyxel support portal to check current firmware version
  3. 3. Download the latest firmware version from Zyxel's official support website (www.zyxel.com/support) for your specific device model
  4. 4. Follow Zyxel's standard firmware upgrade procedure: backup current configuration, upload new firmware, verify installation, restore configuration if needed
  5. 5. After upgrade, verify the XSS vulnerability is resolved by checking release notes or confirming the firmware version is beyond 5.20 (for ATP and VPN series)
Caveat Review Zyxel release notes for potential configuration or feature changes between versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Vpn100 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,150
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-0734 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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