npm · shescape
Shescape: Shell injection via unescaped parentheses on Windows with CMD
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 ""
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.
Alternatively, users of Shescape can remove all instances of ( and ) from untrusted inputs.
Is your project exposed to this? Stateward checks every dependency on every pull request and flags it only if your code actually reaches it.
Check my repoSources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.