CVE-2026-73413: Shescape Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-gm3r-q2wp-hw87
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CWE-400 CWE-407
Published
Advisory Summary

CVE-2026-73413 is a HIGH denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Shescape libraries in the npm ecosystem. The issue involves quadratic-time denial of service in the flag-protection. Remediation is available by upgrading affected packages to version 2.1.14, 3.0.1.

CVE-2026-73413 at a Glance

CVE Identifier CVE-2026-73413
GHSA Identifier GHSA-gm3r-q2wp-hw87
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Shescape
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-73413

To remediate this vulnerability, upgrade all affected Shescape dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

shescape fixed: 2.1.14 
npm install shescape@2.1.14
shescape fixed: 3.0.1 
npm install shescape@3.0.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls shescape

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-73413, inspect your project dependencies using npm:

npm ls shescape

Analyze the terminal output to locate any version of Shescape in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.1.14), your application is affected.

Note: The npm ls shescape command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Shescape, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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 - 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)

CVE-2026-73413 Affected Shescape Versions

2 component(s)
Fixed Versions:
2.1.143.0.1
Product / Package Ecosystem Affected Versions Fixed Version
shescape
npm/shescape
npm
≥ 2.1.11
< 2.1.14
2.1.14
shescape
npm/shescape
npm
≥ 3.0.0
< 3.0.1
3.0.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/ericcornelissen/shescape/security/advisories/GHSA-gm3r-q2wp-hw87
Shescape Source Repository REPOSITORY
https://github.com/ericcornelissen/shescape/pull/2649
Shescape Source Repository REPOSITORY
https://github.com/ericcornelissen/shescape/pull/2651
Security Fix Commit FIX COMMIT
https://github.com/ericcornelissen/shescape/commit/43d70b59d09bbe5c3fd02ef08b3a123e977ed9de
Security Fix Commit FIX COMMIT
https://github.com/ericcornelissen/shescape/commit/b4b34c394e7f9da2775bb75381066b9a228c425f
Shescape Source Repository REPOSITORY
https://github.com/ericcornelissen/shescape
Shescape Source Repository REPOSITORY
https://github.com/ericcornelissen/shescape/blob/dea8893a5877893d8d4923dbf253080e08899e6d/docs/migration.md
Shescape Release RELEASE
https://github.com/ericcornelissen/shescape/releases/tag/v2.1.14
Shescape Release RELEASE
https://github.com/ericcornelissen/shescape/releases/tag/v3.0.1

Frequently Asked Questions

What is CVE-2026-73413?
CVE-2026-73413 is a security vulnerability in Shescape involving Quadratic-time denial of service in the flag-protection under CWE-400: Uncontrolled Resource Consumption.
Which Shescape versions are affected?
Affected versions include releases prior to 2.1.14, 3.0.1 across affected packages: shescape.
What version fixes CVE-2026-73413?
Upgrading to 2.1.14, 3.0.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is shescape affected?
Yes, shescape is affected in releases prior to 2.1.14, 3.0.1. Upgrade your dependency to 2.1.14, 3.0.1 or later.
What CWE is associated with CVE-2026-73413?
CVE-2026-73413 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check npm dependencies for CVE-2026-73413?
Run the dependency tree command: 'npm ls shescape'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-gm3r-q2wp-hw87",
  "modified" : "2026-08-12T19:40:52Z",
  "published" : "2026-07-24T22:35:08Z",
  "aliases" : [ "CVE-2026-73413" ],
  "summary" : "Shescape: Quadratic-time denial of service in the flag-protection",
  "details" : "### Impact\n\nThis impacts users of Shescape that have flag protection enabled, which is on by default, regardless of the API being used.\n\nAn attacker can cause a runtime quadratic in the input size, causing denial of service for large inputs.\n\n```javascript\nimport { Shescape } from \"shescape\";\n\n// 1. Prerequisites\nconst options = {\n    //flagProtection unspecified\n    // Or\n    flagProtection: true,\n};\n\n// 2. Payload\nlet payload = \"\\u0000-\".repeat(32000);\n\n// 3. Usage\nconst shescape = new Shescape(options);\nlet callback;\n\ncallback = () => shescape.escape(payload);\n// Or\ncallback = () => shescape.escapeAll([payload]);\n// Or\ncallback = () => shescape.quote(payload);\n// Or\ncallback = () => shescape.quoteAll([payload]);\n\nconst t0 = process.hrtime.bigint();\ncallback();\nconst ms = Number(process.hrtime.bigint() - t0) / 1e6;\n\n// 4. Impact\nconsole.log(\"Duration:\", ms);\n// Outputs \"Duration:\" followed by a number close to 20000\n```\n\n### Patches\n\nThis bug has been patched in [v2.1.14] and [v3.0.1] which you can upgrade to now.\n\nIf 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.\n\nNo patches will be released for version of Shescape lower than v2.0.0.\n\n### Workarounds\n\nAlternatively, users of Shescape can 1) put restrictions on the length of untrusted input or 2) strip all content before the **last** `-` from untrusted inputs.\n\n### For more information\n\n- Comment on Pull Request [#2651] for v2 and [#2649] for v3\n- Comment on commit [b4b34c3] for v2 and [43d70b5] for v3\n- Open an issue at <https://github.com/ericcornelissen/shescape/issues> (New issue > Question)",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "shescape"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.1.11"
      }, {
        "fixed" : "2.1.14"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "shescape"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "3.0.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/security/advisories/GHSA-gm3r-q2wp-hw87"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/pull/2649"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/pull/2651"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/commit/43d70b59d09bbe5c3fd02ef08b3a123e977ed9de"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/commit/b4b34c394e7f9da2775bb75381066b9a228c425f"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ericcornelissen/shescape"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/blob/dea8893a5877893d8d4923dbf253080e08899e6d/docs/migration.md"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/releases/tag/v2.1.14"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/releases/tag/v3.0.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400", "CWE-407" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-24T22:35:08Z",
    "nvd_published_at" : null
  }
}