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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-42740
• https://www.npmjs.com/package/shell-quote
• ljharb/shell-quote@5799416
• https://github.com/ljharb/shell-quote/blob/master/CHANGELOG.md#173