CVE-2026-73414 — shescape
Fix: ericcornelissen/shescape@43d70b5CVE-2026-73414 is a OS Command Injection vulnerability in shescape. A fix is available for shescape — see the affected versions and patch details below.
Shescape: Shell injection via unescaped parentheses on Windows with CMD
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
shescapenpmDescription
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | shescape | all versions | 2.1.14npm install shescape@2.1.14 |
| 📦npm | shescape | ≥ 3.0.0&&< 3.0.1 | 3.0.1npm install shescape@3.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for shescape, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update shescape to 2.1.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-73414 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-73414 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-73414. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-73414 in your dependencies?
O3 Security finds CVE-2026-73414 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.