PT-2026-42766 · Shell Quote · Shell-Quote

Akshat Sinha + 1 · Published 2026-05-22 · Updated 2026-05-22 · CVE-2026-9277

Mitre

CVSS v3.1

8.1

High

Base vector

AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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 ( , 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: '... ...' } 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.

Fix

Command Injection

OS Command Injection

Weakness Enumeration

CWE-77

CWE-78

Related Identifiers

CVE-2026-9277

Affected Products

Shell-Quote

References · 4

• https://github.com/ljharb/shell-quote/security/advisories/GHSA-w7jw-789q-3m8p · Vendor Advisory
• https://github.com/ljharb/shell-quote/commit/1518179 · Patch
• https://github.com/ljharb/shell-quote · Note
• https://npmjs.com/package/shell-quote · Note