shell-quote: `quote()` command injection via a line terminator in a token after a `{ comment }` token

Why it is Amber

• CVSS 8.1 high
• Remotely exploitable without logging in
• On your watchlist: npm

Affected packages

References

• https://github.com/advisories/GHSA-pqg4-j6r4-53mv
• https://github.com/ljharb/shell-quote/security/advisories/GHSA-pqg4-j6r4-53mv
• https://nvd.nist.gov/vuln/detail/CVE-2026-102422
• https://github.com/ljharb/shell-quote/commit/6002b2ed90c6b83095eb272b6b0adaf3a172b0bc
• https://github.com/advisories/GHSA-pqg4-j6r4-53mv
• https://github.com/ljharb/shell-quote
• https://www.npmjs.com/package/shell-quote

Original description

shell-quote's `quote()` function emits a `{ comment }` token as `#` followed by its text, which comments out the rest of the shell line, including the opening quote of any later string token. A line terminator (\n, \r, U+2028, U+2029) in that later string therefore ends the comment, and the rest of the string is parsed as shell input: `quote(['echo', 'ok', { comment: 'x' }, 'a\nid;#'])` runs `id` in sh, bash, dash, ksh and zsh. `parse()` emits a comment token for a `#` in the middle of a word (for example `http://example.com/#frag`), so callers that combine `parse()` output with another untrusted string, such as `quote(parse(untrustedCommand).concat(untrustedArg))`, are affected. The fix for CVE-2026-9277 rejected line terminators in the comment's own text, but not in the tokens after it. Fixed in 1.11.0: `quote()` throws a `TypeError` when a string after a `{ comment }` token contains a line terminator.