CVE intelligence and bounded remediation

CVE-2018-20334 — An issue was discovered in ASUSWRT 3.0.0.4.384.20308

Critical CVSS 9.8

An issue was discovered in ASUSWRT 3.0.0.4.384.20308. When processing the /start_apply.htm POST data, there is a command injection issue via shell metacharacters in the fb_email parameter. By using this issue, an attacker can control the router and get shell.

Severity
Critical
CVSS
9.8 (3.1)
Published
2020-03-20
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-78

Affected products

  • asus / asuswrt / 3.0.0.4.384.20308

Matched remediation archetype

Command, code, expression, and template injection

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

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

The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.