CVE intelligence and bounded remediation

CVE-2020-5685 — Nec Univerge Sv9500 Firmware security vulnerability

Critical CVSS 9.8

UNIVERGE SV9500 series from V1 to V7and SV8500 series from S6 to S8 allows an attacker to execute arbitrary OS commands or cause a denial-of-service (DoS) condition by sending a specially crafted request to a specific URL.

Severity
Critical
CVSS
9.8 (3.1)
Published
2021-01-13
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-78

Affected products

  • nec / univerge_sv9500_firmware
  • nec / univerge_sv8500_firmware

Matched remediation archetype

Command, code, expression, and template injection

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Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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