CVE intelligence and bounded remediation

CVE-2019-20031 — Nec Um8000 Firmware security vulnerability

Critical CVSS 9.1

NEC UM8000, UM4730 and prior non-InMail voicemail systems with all known software versions may permit an infinite number of login attempts in the telephone user interface (TUI), effectively allowing brute force attacks.

Severity
Critical
CVSS
9.1 (3.1)
Published
2020-07-29
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-307

Affected products

  • nec / um8000_firmware
  • nec / um4730_firmware

Matched remediation archetype

Authentication bypass and missing authentication

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

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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