CVE intelligence and bounded remediation

CVE-2020-29583 — Zyxel Multiple Products Use of Hard-Coded Credentials Vulnerability

Critical CVSS 9.8 CISA KEV

Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can be found in cleartext in the firmware. This account can be used by someone to login to the ssh server or web interface with admin privileges.

Severity
Critical
CVSS
9.8 (3.1)
Published
2020-12-22
CISA KEV
Known exploited
Ecosystem
operating-system
Weaknesses
CWE-522

Affected products

  • zyxel / usg20-vpn_firmware / 4.60
  • zyxel / usg20w-vpn_firmware / 4.60
  • zyxel / usg40_firmware / 4.60
  • zyxel / usg40w_firmware / 4.60
  • zyxel / usg60_firmware / 4.60
  • zyxel / usg60w_firmware / 4.60

Showing 6 representative product identities from 30 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Information disclosure and sensitive data exposure

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

Check exposure

  • Trace sensitive data through responses, errors, logs, metrics, traces, caches, exports, files, backups, and client bundles.
  • Identify affected subjects, tenants, retention windows, access controls, and downstream copies without opening unnecessary sensitive records.
  • Review metadata, timing, status, length, and existence signals as well as direct content disclosure.

Remediate safely

  • Minimize collection and output, apply field-level authorization and redaction at a centralized boundary, and return generic external errors.
  • Remove secrets and sensitive data from logs, artifacts, URLs, caches, and client-side bundles; rotate credentials that may have been exposed.
  • Update the affected component and add synthetic-data tests for response, error, observability, and export paths.

Authoritative sources

Complete CVE record and remediation plan

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