GHSA-pqg4-j6r4-53mv
shell-quote: `quote()` command injection via a line terminator in a token after a `{ comment }` token
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | shell-quote | >= 1.8.4, < 1.11.0 | 1.11.0 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Impact
`quote()` 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 in that later string ends the comment, and the rest of the string is parsed as shell input:
```js
quote(['echo', 'ok', { comment: 'x' }, 'a\nid;#']);
// echo ok #x 'a
// id;#'
```
Passed to `sh`, `bash`, `dash`, `ksh`, or `zsh`, this runs `id`.
`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.
Exploitation requires an attacker-controlled string containing a line terminator that follows a `{ comment }` token in the same `quote()` call.
### Patches
Fixed in v1.11.0: `quote()` throws a `TypeError` when a string after a `{ comment }` token contains a line terminator (`\n`, `\r`, U+2028, or U+2029).
### Workarounds
Drop every token after a `{ comment }` token before calling `quote()`, or reject line terminators in untrusted strings. Separately, do not append other shell text after `quote()` output that contains a comment, since the comment swallows it.
References
External links from the advisory. They lead to third-party sites.