Shescape: Shell injection via unescaped parentheses on Windows with CMD
Impact
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 ""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 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 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)
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | shescape | < 2.1.14, >= 3.0.0, < 3.0.1 | 2.1.14, 3.0.1 |
References
- https://github.com/ericcornelissen/shescape/security/advisories/GHSA-w4hw-qcx7-56pr
- https://github.com/ericcornelissen/shescape/pull/2649
- https://github.com/ericcornelissen/shescape/pull/2651
- https://github.com/ericcornelissen/shescape/commit/43d70b59d09bbe5c3fd02ef08b3a123e977ed9de
- https://github.com/ericcornelissen/shescape/commit/b4b34c394e7f9da2775bb75381066b9a228c425f
- https://github.com/ericcornelissen/shescape
- https://github.com/ericcornelissen/shescape/blob/dea8893a5877893d8d4923dbf253080e08899e6d/docs/migration.md
- https://github.com/ericcornelissen/shescape/releases/tag/v2.1.14
- https://github.com/ericcornelissen/shescape/releases/tag/v3.0.1
- CVSS 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- Weakness (CWE)
CWE-150, CWE-78- Platform
- npm
- Package
shescape- Disclosed
- 24.07.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-w4hw-qcx7-56pr - CC BY 4.0
Vulnerability history: shescape
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 13
- First → latest
- 03.2021 07.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
- High 5
- Medium 4
- Low 2
Disclosures per year
- 2021: 1
- 2022: 4
- 2023: 2
- 2024: 0
- 2025: 1
- 2026: 5
-
Shescape: Shell injection via unescaped parentheses on Windows with CMD this entry
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