Critical

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

  • Disclosed: 06.10.2026
  • Updated: 11.10.2026 10:22

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.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package shell-quote >= 1.8.4, < 1.11.0 1.11.0

References

CVSS score 8.1/10
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

  1. 2019: 1
  2. 2020: 0
  3. 2021: 0
  4. 2022: 1
  5. 2023: 0
  6. 2024: 0
  7. 2025: 0
  8. 2026: 3
  1. shell-quote: `quote()` command injection via a line terminator in a token after a `{ comment }` token this entry
    Critical · 8.1 CVE-2026-102422 >= 1.8.4, < 1.11.0 1.11.0
  2. Critical · 8.1 CVE-2026-9277 >= 1.1.0, < 1.8.4 1.8.4
  3. Critical · 9.8 CVE-2021-42740 >= 1.6.3, < 1.7.3 1.7.3
  4. Critical · 9.8 CVE-2016-10541 < 1.6.1 1.6.1

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