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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 6 Jun 2022.
Usg Flex 100w FirmwareOperating system · Zyxel

CVE-2022-30525

CRITICAL · 9.8 CVSS v3.1 Published 2022-05-12
Fix available
A fix is available. Upgrade to 5.30 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable No privileges Zero-click

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 OS command injection vulnerability in the CGI program of Zyxel USG FLEX 100(W) firmware versions 5.00 through 5.21 Patch 1, USG FLEX 200 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 500 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 700 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 50(W) firmware versions 5.10 through 5.21 Patch 1, USG20(W)-VPN firmware versions 5.10 through 5.21 Patch 1, ATP series firmware versions 5.10 through 5.21 Patch 1, VPN series firmware versions 4.60 through 5.21 Patch 1, which could allow an attacker to modify specific files and then execute some OS commands on a vulnerable 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 confidence

CVE-2022-30525 is a critical OS command injection vulnerability in the CGI program of Zyxel USG FLEX, ATP, and VPN series firewall appliances. The flaw allows authenticated attackers to modify specific configuration files and subsequently execute arbitrary operating system commands on the vulnerable device, achieving full compromise of the network security appliance.

MitigationUpgrade Zyxel firmware to version 5.21 Patch 2 or later. Until patches are applied, strictly limit administrative access to trusted networks and monitor for indicators of compromise.

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
Usg Flex 100w FirmwareOperating system
Affected:>= 5.00, < 5.30
Usg Flex 200 FirmwareOperating system
Affected:>= 5.00, < 5.30
Usg Flex 500 FirmwareOperating system
Affected:>= 5.00, <= 5.30
Usg Flex 700 FirmwareOperating system
Affected:>= 5.00, < 5.30
Vpn100 FirmwareOperating system
Affected:>= 4.60, < 5.30
Vpn1000 FirmwareOperating system
Affected:>= 4.60, < 5.30
Vpn300 FirmwareOperating system
Affected:>= 4.60, < 5.30
Vpn50 FirmwareOperating system
Affected:>= 4.60, < 5.30

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
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 checks

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

  1. Identify the Zyxel device model
    Access the web management interface and locate the device model name, typically found in the dashboard or under System > Status. Alternatively, check the device label or CLI output.
    Affected if The device model is a USG Flex 100w, USG Flex 200, USG Flex 500, USG Flex 700, VPN50, VPN100, VPN300, or VPN1000.
  2. Determine the installed firmware version
    In the web GUI, go to System > Status or Maintenance > Firmware to view the current firmware version. From CLI, use commands such as 'show system-info' or 'sysmond.'
    Affected if The firmware version is 5.00 or higher but lower than 5.30 for USG Flex models, or 4.60 or higher but lower than 5.30 for VPN models.
  3. Verify if the web management interface is exposed to untrusted networks
    Review firewall rules, NAT configurations, or border router settings to determine whether the Zyxel device HTTP/HTTPS management ports (typically 443, 8443) are accessible from outside the trusted internal network or directly from the internet.
    Affected if The management interface is reachable from untrusted networks such as the public internet or DMZ segments without VPN or IP restriction.
  4. Check for unauthorized configuration changes or new accounts
    In the web GUI, review User > Admin Users and Configuration > Backup/Restore for unexpected accounts or configuration modifications. From CLI, use 'show admin-user' or review system logs for suspicious commands.
    Affected if Unexpected administrator accounts, configuration changes, or commands appear that were not authored by legitimate administrators.

A user is affected if the device is a vulnerable USG Flex or VPN model running firmware in the range 4.60 to 5.29 (or 5.00 to 5.29 for Flex models) AND the management interface is accessible from untrusted networks.

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 5.30 or later
Fixed in 5.30
Interim mitigation

Upgrade Zyxel firmware to version 5.21 Patch 2 or later. Until patches are applied, strictly limit administrative access to trusted networks and monitor for indicators of compromise.

Recommended fix High confidence

Zyxel USG FLEX/VPN/ATP series firmware version 5.30 or later

  1. 1. Identify the exact model number and current firmware version of the Zyxel device (USG Flex, VPN, or ATP series).
  2. 2. Download the latest firmware version 5.30 or later from the official Zyxel support website (www.zyxel.com/support/download.shtml).
  3. 3. Back up the current device configuration through the web management interface or CLI.
  4. 4. Access the device's web management interface and navigate to Maintenance > Firmware Upgrade.
  5. 5. Upload the downloaded firmware file (version 5.30 or later) and initiate the upgrade process.
  6. 6. Wait for the firmware upgrade to complete - do not power off the device during this process.
  7. 7. After reboot, verify the firmware version has been updated successfully.
  8. 8. Restore the configuration backup if needed and verify all services are functioning properly.
Caveat Review Zyxel release notes for version 5.30 to check for any configuration or feature changes that may require adjustment

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

Fix this in Usg Flex 100w Firmware Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2022-30525 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