CVE intelligence and bounded remediation

CVE-2023-33239 — Moxa Tn-5900 Firmware security vulnerability

Critical CVSS 9.8

TN-4900 Series firmware versions v1.2.4 and prior and TN-5900 Series firmware versions v3.3 and prior are vulnerable to the command injection vulnerability. This vulnerability stems from insufficient input validation in the key-generation function, which could potentially allow malicious users to execute remote code on affected devices.

Severity
Critical
CVSS
9.8 (3.1)
Published
2023-08-17
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-78, CWE-77

Affected products

  • moxa / tn-5900_firmware
  • moxa / tn-4900_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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