CVE-2026-30916: Withdrawn Advisory Shescape Has Possible Misidentification Of Vulnerability

LOW
Advisory Identifier: GHSA-6f6w-6j58-rq76
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CWE-200
Published
Advisory Summary

CVE-2026-30916 is a LOW shescape has possible misidentification of vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting Withdrawn Advisory libraries in the npm ecosystem. The issue involves shescape has possible misidentification of shell due to link chains. Remediation is available by upgrading affected packages to version 2.1.9.

CVE-2026-30916 at a Glance

CVE Identifier CVE-2026-30916
GHSA Identifier GHSA-6f6w-6j58-rq76
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Affected Product Withdrawn Advisory
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-30916

To remediate this vulnerability, upgrade all affected Withdrawn Advisory dependencies to a patched release.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: 2.1.9 
npm install shescape@2.1.9
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-2026-30916, inspect your project dependencies using npm:

npm ls shescape

Analyze the terminal output to locate any version of Withdrawn Advisory in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.1.9), 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-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. In Withdrawn Advisory, software state validation or input boundaries are circumvented during processing.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

## Withdrawn Advisory This advisory has been withdrawn because it falls outside the https://github.com/ericcornelissen/shescape/blob/a2544a1c78cae19d0e81a485b997bf0b0fcc2c12/SECURITY.md#threat-model. This link is maintained to preserve external references. ## Original Description ### Impact This impacts users of Shescape that configure their `shell` to point to a file on disk that is a link to a link. The precise result of being affected depends on the actual shell used and incorrect shell identified by Shescape. In particular, an attacker may be able to bypass escaping for the shell being used. This can result, for example, in exposure of sensitive information, consider the following proof of concept (targeting Shescape v2): ```javascript import fs from "node:fs"; import { exec } from "node:child_process"; import { Shescape } from "shescape"; import which from "which"; /* 1. Set up */ const shell = which.sync("bash"); const linkToShell = "./csh"; const linkToLink = "./link"; fs.rmSync(linkToLink, { force: true }); fs.rmSync(linkToShell, { force: true }); fs.symlinkSync(shell, linkToShell); fs.symlinkSync(linkToShell, linkToLink); /* 2. Misconfiguration */ const execOptions = { shell: linkToLink, }; const shescape = new Shescape({ shell: execOptions.shell, }); /* 3. Payload */ const userInput = "a=:~"; /* 4. Attack example */ exec( `echo Hello ${shescape.escape(userInput)}`, { shell: execOptions.shell }, (error, stdout) => { fs.rmSync(linkToLink); fs.rmSync(linkToShell); if (error) { console.error(`An error occurred: ${error}`); } else { console.log(stdout); // Output: "Hello a=:/home/user" } }, ); ``` ### Patches This problem has been patched in [v2.1.9](https://www.npmjs.com/package/shescape/v/2.1.9) which you can upgrade to now. ### Workarounds If upgrading is not an option, either avoid using a shell or make sure the shell path you use is not a link to a link. ### References - Shescape Pull Request [#2388](https://github.com/ericcornelissen/shescape/pull/2388) - Shescape Release [v2.1.9](https://github.com/ericcornelissen/shescape/releases/tag/v2.1.9) ### For more information - Comment on Pull Request [#2388](https://github.com/ericcornelissen/shescape/pull/2388) - Open an issue at <https://github.com/ericcornelissen/shescape/issues> (New issue > Question)

CVE-2026-30916 Affected Withdrawn Advisory Versions

1 component(s)
Fixed Versions:
2.1.9
Product / Package Ecosystem Affected Versions Fixed Version
shescape
npm/shescape
npm
< 2.1.9
2.1.9

References

GitHub Advisory / Wiki ADVISORY
https://github.com/ericcornelissen/shescape/security/advisories/GHSA-6f6w-6j58-rq76
NVD — CVE-2026-30916 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-30916
Withdrawn Advisory Source Repository REPOSITORY
https://github.com/ericcornelissen/shescape/pull/2388
Withdrawn Advisory Source Repository REPOSITORY
https://github.com/github/advisory-database/pull/7206
Withdrawn Advisory Source Repository REPOSITORY
https://github.com/ericcornelissen/shescape
Withdrawn Advisory Release RELEASE
https://github.com/ericcornelissen/shescape/releases/tag/v2.1.9
www.npmjs.com/package/shescape/v/... WEB
https://www.npmjs.com/package/shescape/v/2.1.9

Frequently Asked Questions

What is CVE-2026-30916?
CVE-2026-30916 is a security vulnerability in Withdrawn Advisory involving Shescape has possible misidentification of shell due to link chains under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor.
Which Withdrawn Advisory versions are affected?
Affected versions include releases prior to 2.1.9 across affected packages: shescape.
What version fixes CVE-2026-30916?
Upgrading to 2.1.9 (or the latest patched release for your respective branch) resolves the vulnerability.
Is shescape affected?
Yes, shescape is affected in releases prior to 2.1.9. Upgrade your dependency to 2.1.9 or later.
What CWE is associated with CVE-2026-30916?
CVE-2026-30916 is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor (The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.).
How can I check npm dependencies for CVE-2026-30916?
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-6f6w-6j58-rq76",
  "modified" : "2026-03-20T19:53:41Z",
  "published" : "2026-03-07T02:31:58Z",
  "withdrawn" : "2026-03-20T19:53:41Z",
  "aliases" : [ "CVE-2026-30916" ],
  "summary" : "Withdrawn Advisory: Shescape has possible misidentification of shell due to link chains",
  "details" : "## Withdrawn Advisory\n\nThis advisory has been withdrawn because it falls outside the https://github.com/ericcornelissen/shescape/blob/a2544a1c78cae19d0e81a485b997bf0b0fcc2c12/SECURITY.md#threat-model. This link is maintained to preserve external references.\n\n## Original Description\n### Impact\n\nThis impacts users of Shescape that configure their `shell` to point to a file on disk that is a link to a link. The precise result of being affected depends on the actual shell used and incorrect shell identified by Shescape.\n\nIn particular, an attacker may be able to bypass escaping for the shell being used. This can result, for example, in exposure of sensitive information, consider the following proof of concept (targeting Shescape v2):\n\n```javascript\nimport fs from \"node:fs\";\nimport { exec } from \"node:child_process\";\n\nimport { Shescape } from \"shescape\";\nimport which from \"which\";\n\n/* 1. Set up */\nconst shell = which.sync(\"bash\");\nconst linkToShell = \"./csh\";\nconst linkToLink = \"./link\";\n\nfs.rmSync(linkToLink, { force: true });\nfs.rmSync(linkToShell, { force: true });\nfs.symlinkSync(shell, linkToShell);\nfs.symlinkSync(linkToShell, linkToLink);\n\n/* 2. Misconfiguration */\nconst execOptions = {\n  shell: linkToLink,\n};\n\nconst shescape = new Shescape({\n  shell: execOptions.shell,\n});\n\n/* 3. Payload */\nconst userInput = \"a=:~\";\n\n/* 4. Attack example */\nexec(\n  `echo Hello ${shescape.escape(userInput)}`,\n  { shell: execOptions.shell },\n  (error, stdout) => {\n    fs.rmSync(linkToLink);\n    fs.rmSync(linkToShell);\n\n    if (error) {\n      console.error(`An error occurred: ${error}`);\n    } else {\n      console.log(stdout);\n      // Output:  \"Hello a=:/home/user\"\n    }\n  },\n);\n```\n\n### Patches\n\nThis problem has been patched in [v2.1.9](https://www.npmjs.com/package/shescape/v/2.1.9) which you can upgrade to now.\n\n### Workarounds\n\nIf upgrading is not an option, either avoid using a shell or make sure the shell path you use is not a link to a link.\n\n### References\n\n- Shescape Pull Request [#2388](https://github.com/ericcornelissen/shescape/pull/2388)\n- Shescape Release [v2.1.9](https://github.com/ericcornelissen/shescape/releases/tag/v2.1.9)\n\n### For more information\n\n- Comment on Pull Request [#2388](https://github.com/ericcornelissen/shescape/pull/2388)\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:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "shescape"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.9"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.1.8"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/security/advisories/GHSA-6f6w-6j58-rq76"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-30916"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/pull/2388"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/github/advisory-database/pull/7206"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ericcornelissen/shescape"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ericcornelissen/shescape/releases/tag/v2.1.9"
  }, {
    "type" : "WEB",
    "url" : "https://www.npmjs.com/package/shescape/v/2.1.9"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-07T02:31:58Z",
    "nvd_published_at" : "2026-03-10T17:40:15Z"
  }
}