CVE intelligence and bounded remediation

CVE-2019-17354 — Zyxel Nbg-418N V2 Firmware security vulnerability

Critical CVSS 9.4

wan.htm page on Zyxel NBG-418N v2 with firmware version V1.00(AARP.9)C0 can be accessed directly without authentication, which can lead to disclosure of information about the WAN, and can also be leveraged by an attacker to modify data fields of the page.

Severity
Critical
CVSS
9.4 (3.1)
Published
2019-10-09
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-306

Affected products

  • zyxel / nbg-418n_v2_firmware / 1.00(aarp.9)c0

Matched remediation archetype

Authentication bypass and missing authentication

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Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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