{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-8723",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-8723",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-05-16T23:21:16.035Z",
    "updatedAt": "2026-05-18T14:02:57.825Z",
    "importedAt": "2026-10-24T01:58:35.090Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "qs.stringify crashes on null/undefined entries in comma-format arrays under encodeValuesOnly",
      "summary": "### Summary\n\n\n\n`qs.stringify` throws `TypeError` when called with `arrayFormat: 'comma'` and `encodeValuesOnly: true` on an array containing `null` or `undefined`. The throw is synchronous and not handled by any of qs's null-related options (`skipNulls`, `strictNullHandling`).\n\n\n\n### Details\n\n\n\nIn the comma + `encodeValuesOnly` branch, `lib/stringify.js:145` mapped the array through the raw encoder before joining:\n\n\n\n```js\n\n\n\nobj = utils.maybeMap(obj, encoder);\n\n\n\n```\n\n\n\n`utils.encode` (`lib/utils.js:195`) reads `str.length` with no null guard, so a `null` or `undefined` element throws `TypeError`. `skipNulls` and `strictNullHandling` are both checked in the per-element loop below this line and never get a chance to run.\n\n\n\nSame class of bug as the filter-array path fixed in 0c180a4. The vulnerable shape of the comma + `encodeValuesOnly` branch was introduced in 4c4b23d (\"encode comma values more consistently\", PR #463, 2023-01-19), first released in v6.11.1.\n\n\n\n#### PoC\n\n\n\n```js\n\n\n\nconst qs = require('qs');\n\n\n\nqs.stringify({ a: [null, 'b'] },      { arrayFormat: 'comma', encodeValuesOnly: true });\n\n\n\nqs.stringify({ a: [undefined, 'b'] }, { arrayFormat: 'comma', encodeValuesOnly: true });\n\n\n\nqs.stringify({ a: [null] },           { arrayFormat: 'comma', encodeValuesOnly: true });\n\n\n\n// TypeError: Cannot read properties of null (reading 'length')\n\n\n\n//     at encode (lib/utils.js:195:13)\n\n\n\n//     at Object.maybeMap (lib/utils.js:322:37)\n\n\n\n//     at stringify (lib/stringify.js:145:25)\n\n\n\n```\n\n\n\n#### Fix\n\n\n\n`lib/stringify.js:145`, applied in 21f80b3 on `main` and released as v6.15.2:\n\n\n\n```diff\n\n\n\n- obj = utils.maybeMap(obj, encoder);\n\n\n\n+ obj = utils.maybeMap(obj, function (v) {\n\n\n\n+     return v == null ? v : encoder(v);\n\n\n\n+ });\n\n\n\n```\n\n\n\n`null` and `undefined` now pass through `maybeMap` unchanged and reach the `join(',')` step as-is. For `{ a: [null, 'b'] }` this produces `a=,b`, matching the non-`encodeValuesOnly` comma path (which already joins before encoding and produces `a=%2Cb` for the same input). Single-element `[null]` arrays still collapse via the existing `obj.join(',') || null` and remain subject to `skipNulls` / `strictNullHandling` in the main loop.\n\n\n\n### Affected versions\n\n\n\n`>=6.11.1 <6.15.2` — fixed in v6.15.2.\n\n\n\nThe vulnerable code shape was introduced in 4c4b23d and first shipped in v6.11.1. Earlier versions — including all of 6.7.x, 6.8.x, 6.9.x, 6.10.x, and 6.11.0 — implemented the comma + `encodeValuesOnly` path differently (joining before encoding) and are not affected. Empirically verified across released versions.\n\n\n\n### Impact\n\n\n\nApplication code that calls `qs.stringify` with both `arrayFormat: 'comma'` and `encodeValuesOnly: true` (both non-default) on input that may contain a `null` or `undefined` array element will throw synchronously instead of producing a query string. In a typical Node.js HTTP framework (Express, Fastify, Koa, hapi) the sync throw is caught by the framework's error boundary and the affected request returns a 500; the worker process does not exit and subsequent requests are unaffected. The \"kills the worker process\" framing applies only to call sites outside a request-handler error boundary (background jobs, startup paths, stream pipelines) or to deployments with framework error handling explicitly disabled.\n\n\n\nThe vulnerable input is a `null` or `undefined` entry inside an array; this is reachable from JSON request bodies or from application code constructing arrays from user input, but not from standard HTML form submissions (which produce strings or omitted fields, not literal `null`).",
      "affected": [
        {
          "vendor": "ljharb",
          "product": "qs",
          "packageName": "qs",
          "collectionURL": "https://npmjs.com/qs",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "6.11.1",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.15.2"
            }
          ]
        }
      ]
    }
  }
}