CVE intelligence and bounded remediation

CVE-2023-22916 — Zyxel Usg Flex 100 Firmware security vulnerability

High CVSS 8.1

The configuration parser of Zyxel ATP series firmware versions 5.10 through 5.35, USG FLEX series firmware versions 5.00 through 5.35, USG FLEX 50(W) firmware versions 5.10 through 5.35, USG20(W)-VPN firmware versions 5.10 through 5.35, and VPN series firmware versions 5.00 through 5.35, which fails to properly sanitize user input. A remote unauthenticated attacker could leverage the vulnerability to modify device configuration data, resulting in DoS conditions on an affected device if the attacker could trick an authorized administrator to switch the management mode to the cloud mode.

Severity
High
CVSS
8.1 (3.1)
Published
2023-04-24
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-20

Affected products

  • zyxel / usg_flex_100_firmware
  • zyxel / usg_flex_100w_firmware
  • zyxel / usg_flex_200_firmware
  • zyxel / usg_flex_50_firmware
  • zyxel / usg_flex_50w_firmware
  • zyxel / usg_flex_500_firmware

Showing 6 representative product identities from 18 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

General vulnerability remediation

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

Check exposure

  • Confirm the affected component, deployment paths, reachable interfaces, and enabled features from inventories and configuration, without probing production destructively.
  • Compare the advisory's affected conditions with the repository lockfiles, build manifests, artifacts, and runtime inventory.
  • Identify data sensitivity, trust boundaries, and privilege level for every confirmed affected deployment.

Remediate safely

  • Apply a vendor-supported fix or remove the affected component or feature; record the selected change and its source in the repository.
  • Update direct and transitive dependency locks, generated artifacts, deployment manifests, and asset inventories together.
  • Add a regression test for the documented unsafe condition using inert inputs and preserve rollback instructions.

Authoritative sources

Complete CVE record and remediation plan

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