GHSA-W4HW-QCX7-56PR

Shescape: Shell injection via unescaped parentheses on Windows with CMD

Workarounds

Alternatively, users of Shescape can remove all instances of ( and ) from untrusted inputs.

For more information

• Comment on Pull Request [#2651] for v2 and [#2649] for v3
• Comment on commit [b4b34c3] for v2 and [43d70b5] for v3
• Open an issue at https://github.com/ericcornelissen/shescape/issues (New issue > Question)

This impacts users of Shescape on Windows that explicitly configure shell to CMD, or true with the default shell being CMD, using the escape and escapeAll APIs.

An attacker may be able to achieve shell injection depending on the original command.

import * as cp from "node:child_process";
import { Shescape } from "shescape";

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

// 2. Payload
const payload = "x) else if a==a (echo y";

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

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

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

// 4. Impact
console.log(result.toString());
// Outputs "y" instead of ""

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

Kodem intelligence

Already deployed Kodem?

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 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.

1. What is GHSA-W4HW-QCX7-56PR? GHSA-W4HW-QCX7-56PR is a critical-severity OS command injection vulnerability in shescape (npm), affecting versions < 2.1.14. It is fixed in 2.1.14, 3.0.1. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
2. Which versions of shescape are affected by GHSA-W4HW-QCX7-56PR? shescape (npm) versions < 2.1.14 is affected.
3. Is there a fix for GHSA-W4HW-QCX7-56PR? Yes. GHSA-W4HW-QCX7-56PR is fixed in 2.1.14, 3.0.1. Upgrade to this version or later.
4. Is GHSA-W4HW-QCX7-56PR exploitable, and should I be worried? Whether GHSA-W4HW-QCX7-56PR is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether GHSA-W4HW-QCX7-56PR is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix GHSA-W4HW-QCX7-56PR?
   • Upgrade shescape to 2.1.14 or later
   • Upgrade shescape to 3.0.1 or later

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