CVE intelligence and bounded remediation

CVE-2021-42740 — The shell-quote package before 1.7.3 for Node.js allows command injection

Critical CVSS 9.8

The shell-quote package before 1.7.3 for Node.js allows command injection. An attacker can inject unescaped shell metacharacters through a regex designed to support Windows drive letters. If the output of this package is passed to a real shell as a quoted argument to a command with exec(), an attacker can inject arbitrary commands. This is because the Windows drive letter regex character class is {A-z] instead of the correct {A-Za-z]. Several shell metacharacters exist in the space between capital letter Z and lower case letter a, such as the backtick character.

Severity
Critical
CVSS
9.8 (3.1)
Published
2021-10-21
CISA KEV
Not currently listed
Ecosystem
windows/system
Weaknesses
CWE-77

Affected products

  • shell-quote_project / shell-quote

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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