Description
shell-quote's `quote()` function did not validate object-token inputs against the operator model used by `parse()`. The `.op` field was backslash-escaped character by character using `/(.)/g`, which in JavaScript does not match line terminators (\n, \r, U+2028, U+2029). A line terminator in `.op` therefore passed through unescaped into the output; POSIX shells treat a literal newline as a command separator, so any content after it would execute as a second command. The vulnerable code path is reachable in two ways: (1) direct construction of `{ op: '...\n...' }` from external input, and (2) via `parse(cmd, envFn)` when `envFn` returns object tokens whose `.op` is attacker-influenced. Both are documented API surface. Fixed by replacing the per-character escape with strict shape validation: `.op` must match the parser's control-operator allowlist; `{ op: 'glob', pattern }` validates `pattern` and forbids line terminators; `{ comment }` validates `comment` and forbids line terminators; any other object shape throws `TypeError`.
Published: 2026-05-22
Score: 9.2 Critical
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6300-1 node-shell-quote security update
Github GHSA Github GHSA GHSA-w7jw-789q-3m8p shell-quote quote() does not escape newlines in object .op values
Ubuntu USN Ubuntu USN USN-8410-1 shell-quote vulnerability
History

Tue, 26 May 2026 13:45:00 +0000

Type Values Removed Values Added
References

Mon, 25 May 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Ljharb
Ljharb shell-quote
Vendors & Products Ljharb
Ljharb shell-quote
References
Metrics threat_severity

None

threat_severity

Important


Fri, 22 May 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 22 May 2026 13:45:00 +0000

Type Values Removed Values Added
Description shell-quote's `quote()` function did not validate object-token inputs against the operator model used by `parse()`. The `.op` field was backslash-escaped character by character using `/(.)/g`, which in JavaScript does not match line terminators (\n, \r, U+2028, U+2029). A line terminator in `.op` therefore passed through unescaped into the output; POSIX shells treat a literal newline as a command separator, so any content after it would execute as a second command. The vulnerable code path is reachable in two ways: (1) direct construction of `{ op: '...\n...' }` from external input, and (2) via `parse(cmd, envFn)` when `envFn` returns object tokens whose `.op` is attacker-influenced. Both are documented API surface. Fixed by replacing the per-character escape with strict shape validation: `.op` must match the parser's control-operator allowlist; `{ op: 'glob', pattern }` validates `pattern` and forbids line terminators; `{ comment }` validates `comment` and forbids line terminators; any other object shape throws `TypeError`.
Title shell-quote `quote()` does not validate object-token shapes, allowing command injection via line terminators in `.op`
Weaknesses CWE-77
CWE-78
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


Subscriptions

Ljharb Shell-quote
cve-icon MITRE

Status: PUBLISHED

Assigner: harborist

Published:

Updated: 2026-05-23T03:04:40.537Z

Reserved: 2026-05-22T12:13:25.893Z

Link: CVE-2026-9277

cve-icon Vulnrichment

Updated: 2026-05-22T14:17:25.193Z

cve-icon NVD

Status : Deferred

Published: 2026-05-22T14:16:30.330

Modified: 2026-06-17T11:05:00.067

Link: CVE-2026-9277

cve-icon Redhat

Severity : Important

Publid Date: 2026-05-22T13:22:38Z

Links: CVE-2026-9277 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-25T11:34:21Z

Weaknesses