shell-quote: `quote()` command injection via a line terminator in a token after a `{ comment }` token
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:
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | shell-quote | >= 1.8.4, < 1.11.0 | 1.11.0 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-78- Platform
- npm
- Package
shell-quote- Disclosed
- 06.10.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-pqg4-j6r4-53mv - CC BY 4.0
Vulnerability history: shell-quote
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 5
- First → latest
- 02.2019 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 4
- High 1
Disclosures per year
- 2019: 1
- 2020: 0
- 2021: 0
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 3
-
shell-quote: `quote()` command injection via a line terminator in a token after a `{ comment }` token this entry
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