IRONSMITHINTEL
CRITICALCVSS9.8
|
Actively Exploited
|CISA KEV|CVE-2022-30525|Auth: none — unauthenticated|Reboot: required|Manual only

Zyxel Multiple Firewalls OS Command Injection Vulnerability (CVE-2022-30525)

A command injection vulnerability in the CGI program of some Zyxel firewall versions could allow an attacker to modify specific files and then execute some OS commands on a vulnerable device.

Published May 12, 2022 · Updated May 17, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2022-06-06 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a OS Command Injection (CWE-78) vulnerability in Zyxel Multiple Firewalls. 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. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

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Phishing link

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Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

●IT Security
●Running usg flex 100w firmware: 5.00 ≤ v < 5.30; usg flex 200 firmware: 5.00 ≤ v < 5.30; usg flex 500 firmware: 5.00 ≤ v ≤ 5.30; usg flex 700 firmware: 5.00 ≤ v < 5.30; vpn100 firmware: 4.60 ≤ v < 5.30; vpn1000 firmware: 4.60 ≤ v < 5.30; vpn300 firmware: 4.60 ≤ v < 5.30; vpn50 firmware: 4.60 ≤ v < 5.30; atp100 firmware: 5.10 ≤ v < 5.30; atp100w firmware: 5.10 ≤ v < 5.30; atp200 firmware: 5.10 ≤ v < 5.30; atp500 firmware: 5.10 ≤ v < 5.30; atp700 firmware: 5.10 ≤ v < 5.30; atp800 firmware: 5.10 ≤ v < 5.30; usg flex 50w firmware: 5.10 ≤ v < 5.30; usg20w-vpn firmware: 5.10 ≤ v < 5.30
Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: http://packetstormsecurity.com/files/167182/Zyxel-Firewall-ZTP-Unauthenticated-Command-Injection.html

How to patch

Manual remediation steps

1
Identify affected hosts: query inventory for general installs in scope.
2
Apply the vendor security update referenced in CVE-2022-30525's advisory. No specific KB/version is encoded yet — consult the linked MSRC/vendor URL.
3
Verify the fix per the vendor's published verification steps.
4
Document the remediation in your change ticket and re-scan with your vulnerability scanner to confirm closure.
PowerShell automationComing soon

No tested PowerShell script for this entry yet. We’re prioritising automation based on user demand.

References

↗ CVE-2022-30525↗ MSRC Advisory↗ NVD↗ Vendor Advisory