What’s Vulnerable › Vulnerabilities

CVE-2021-42740

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-21 · updated 2026-06-17
• Weakness: CWE-77

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.

Affected products

• ljharb shell-quote: before 1.7.3 — fixed in 1.7.3

How to fix

Upgrade to a fixed version: ljharb shell-quote 1.7.3. Check the vendor advisory for mitigations.

References

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

Get alerted when CVE-2021-42740 or the next vulnerability affects your stack