CVE intelligence and bounded remediation

CVE-2022-2030 — Zyxel Usg Flex 100W Firmware security vulnerability

Medium CVSS 6.5

A directory traversal vulnerability caused by specific character sequences within an improperly sanitized URL was identified in some CGI programs of Zyxel USG FLEX 100(W) firmware versions 4.50 through 5.30, USG FLEX 200 firmware versions 4.50 through 5.30, USG FLEX 500 firmware versions 4.50 through 5.30, USG FLEX 700 firmware versions 4.50 through 5.30, USG FLEX 50(W) firmware versions 4.16 through 5.30, USG20(W)-VPN firmware versions 4.16 through 5.30, ATP series firmware versions 4.32 through 5.30, VPN series firmware versions 4.30 through 5.30, USG/ZyWALL series firmware versions 4.11 through 4.72, that could allow an authenticated attacker to access some restricted files on a vulnerable device.

Severity
Medium
CVSS
6.5 (3.1)
Published
2022-07-19
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-22

Affected products

  • zyxel / usg_flex_100w_firmware
  • zyxel / usg_flex_200_firmware
  • zyxel / usg_flex_500_firmware
  • zyxel / usg_flex_700_firmware
  • zyxel / usg_flex_50w_firmware
  • zyxel / usg20w-vpn_firmware

Showing 6 representative product identities from 25 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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