CVE intelligence and bounded remediation

CVE-2022-30525 — Zyxel Multiple Firewalls OS Command Injection Vulnerability

Critical CVSS 9.8 CISA KEV

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.

Severity
Critical
CVSS
9.8 (3.1)
Published
2022-05-12
CISA KEV
Known exploited
Ecosystem
operating-system
Weaknesses
CWE-78

Affected products

  • zyxel / usg_flex_100w_firmware
  • zyxel / usg_flex_200_firmware
  • zyxel / usg_flex_500_firmware
  • zyxel / usg_flex_700_firmware
  • zyxel / vpn100_firmware
  • zyxel / vpn1000_firmware

Showing 6 representative product identities from 16 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Command, code, expression, and template injection

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Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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