CVE-2026-2391 (GCVE-0-2026-2391)

Vulnerability from cvelistv5 – Published: 2026-02-12 04:39 – Updated: 2026-02-12 17:32
VLAI
Title
qs's arrayLimit bypass in comma parsing allows denial of service
Summary
### Summary The `arrayLimit` option in qs does not enforce limits for comma-separated values when `comma: true` is enabled, allowing attackers to cause denial-of-service via memory exhaustion. This is a bypass of the array limit enforcement, similar to the bracket notation bypass addressed in GHSA-6rw7-vpxm-498p (CVE-2025-15284). ### Details When the `comma` option is set to `true` (not the default, but configurable in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `['a', 'b', 'c']`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of arbitrarily large arrays from a single parameter, leading to excessive memory allocation. **Vulnerable code** (lib/parse.js: lines ~40-50): ```js if (val && typeof val === 'string' && options.comma && val.indexOf(',') > -1) {     return val.split(','); } if (options.throwOnLimitExceeded && currentArrayLength >= options.arrayLimit) {     throw new RangeError('Array limit exceeded. Only ' + options.arrayLimit + ' element' + (options.arrayLimit === 1 ? '' : 's') + ' allowed in an array.'); } return val; ``` The `split(',')` returns the array immediately, skipping the subsequent limit check. Downstream merging via `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`), allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`, which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in v6.14.1 per GHSA-6rw7-vpxm-498p). ### PoC **Test 1 - Basic bypass:** ``` npm install qs ``` ```js const qs = require('qs'); const payload = 'a=' + ','.repeat(25); // 26 elements after split (bypasses arrayLimit: 5) const options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true }; try {   const result = qs.parse(payload, options);   console.log(result.a.length); // Outputs: 26 (bypass successful) } catch (e) {   console.log('Limit enforced:', e.message); // Not thrown } ``` **Configuration:** - `comma: true` - `arrayLimit: 5` - `throwOnLimitExceeded: true` Expected: Throws "Array limit exceeded" error. Actual: Parses successfully, creating an array of length 26. ### Impact Denial of Service (DoS) via memory exhaustion.
Severity
6.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
3.7 (Low)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-20 - Improper Input Validation
Assigner
References
Impacted products
Vendor Product Version
Affected: 6.7.0 , ≤ 6.14.1 (semver)
Show details on NVD website
To clipboard 

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              "value": "### Summary\u003cbr\u003eThe `arrayLimit` option in qs does not enforce limits for comma-separated values when `comma: true` is enabled, allowing attackers to cause denial-of-service via memory exhaustion. This is a bypass of the array limit enforcement, similar to the bracket notation bypass addressed in GHSA-6rw7-vpxm-498p (CVE-2025-15284).\u003cbr\u003e\u003cbr\u003e### Details\u003cbr\u003eWhen the `comma` option is set to `true` (not the default, but configurable in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `[\u0027a\u0027, \u0027b\u0027, \u0027c\u0027]`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of arbitrarily large arrays from a single parameter, leading to excessive memory allocation.\u003cbr\u003e\u003cbr\u003e**Vulnerable code** (lib/parse.js: lines ~40-50):\u003cbr\u003e```js\u003cbr\u003eif (val \u0026amp;\u0026amp; typeof val === \u0027string\u0027 \u0026amp;\u0026amp; options.comma \u0026amp;\u0026amp; val.indexOf(\u0027,\u0027) \u0026gt; -1) {\u003cbr\u003e\u0026nbsp; \u0026nbsp; return val.split(\u0027,\u0027);\u003cbr\u003e}\u003cbr\u003e\u003cbr\u003eif (options.throwOnLimitExceeded \u0026amp;\u0026amp; currentArrayLength \u0026gt;= options.arrayLimit) {\u003cbr\u003e\u0026nbsp; \u0026nbsp; throw new RangeError(\u0027Array limit exceeded. Only \u0027 + options.arrayLimit + \u0027 element\u0027 + (options.arrayLimit === 1 ? \u0027\u0027 : \u0027s\u0027) + \u0027 allowed in an array.\u0027);\u003cbr\u003e}\u003cbr\u003e\u003cbr\u003ereturn val;\u003cbr\u003e```\u003cbr\u003eThe `split(\u0027,\u0027)` returns the array immediately, skipping the subsequent limit check. Downstream merging via `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`), allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`, which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in v6.14.1 per GHSA-6rw7-vpxm-498p).\u003cbr\u003e\u003cbr\u003e### PoC\u003cbr\u003e**Test 1 - Basic bypass:**\u003cbr\u003e```\u003cbr\u003enpm install qs\u003cbr\u003e```\u003cbr\u003e\u003cbr\u003e```js\u003cbr\u003econst qs = require(\u0027qs\u0027);\u003cbr\u003e\u003cbr\u003econst payload = \u0027a=\u0027 + \u0027,\u0027.repeat(25);  // 26 elements after split (bypasses arrayLimit: 5)\u003cbr\u003econst options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true };\u003cbr\u003e\u003cbr\u003etry {\u003cbr\u003e\u0026nbsp; const result = qs.parse(payload, options);\u003cbr\u003e\u0026nbsp; console.log(result.a.length);  // Outputs: 26 (bypass successful)\u003cbr\u003e} catch (e) {\u003cbr\u003e\u0026nbsp; console.log(\u0027Limit enforced:\u0027, e.message);  // Not thrown\u003cbr\u003e}\u003cbr\u003e```\u003cbr\u003e**Configuration:**\u003cbr\u003e- `comma: true`\u003cbr\u003e- `arrayLimit: 5`\u003cbr\u003e- `throwOnLimitExceeded: true`\u003cbr\u003e\u003cbr\u003eExpected: Throws \"Array limit exceeded\" error.\u003cbr\u003eActual: Parses successfully, creating an array of length 26.\u003cbr\u003e\u003cbr\u003e\u003cbr\u003e### Impact\u003cbr\u003eDenial of Service (DoS) via memory exhaustion.\u003cbr\u003e"
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          "value": "### Summary\nThe `arrayLimit` option in qs does not enforce limits for comma-separated values when `comma: true` is enabled, allowing attackers to cause denial-of-service via memory exhaustion. This is a bypass of the array limit enforcement, similar to the bracket notation bypass addressed in GHSA-6rw7-vpxm-498p (CVE-2025-15284).\n\n### Details\nWhen the `comma` option is set to `true` (not the default, but configurable in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `[\u0027a\u0027, \u0027b\u0027, \u0027c\u0027]`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of arbitrarily large arrays from a single parameter, leading to excessive memory allocation.\n\n**Vulnerable code** (lib/parse.js: lines ~40-50):\n```js\nif (val \u0026\u0026 typeof val === \u0027string\u0027 \u0026\u0026 options.comma \u0026\u0026 val.indexOf(\u0027,\u0027) \u003e -1) {\n\u00a0 \u00a0 return val.split(\u0027,\u0027);\n}\n\nif (options.throwOnLimitExceeded \u0026\u0026 currentArrayLength \u003e= options.arrayLimit) {\n\u00a0 \u00a0 throw new RangeError(\u0027Array limit exceeded. Only \u0027 + options.arrayLimit + \u0027 element\u0027 + (options.arrayLimit === 1 ? \u0027\u0027 : \u0027s\u0027) + \u0027 allowed in an array.\u0027);\n}\n\nreturn val;\n```\nThe `split(\u0027,\u0027)` returns the array immediately, skipping the subsequent limit check. Downstream merging via `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`), allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`, which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in v6.14.1 per GHSA-6rw7-vpxm-498p).\n\n### PoC\n**Test 1 - Basic bypass:**\n```\nnpm install qs\n```\n\n```js\nconst qs = require(\u0027qs\u0027);\n\nconst payload = \u0027a=\u0027 + \u0027,\u0027.repeat(25);  // 26 elements after split (bypasses arrayLimit: 5)\nconst options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true };\n\ntry {\n\u00a0 const result = qs.parse(payload, options);\n\u00a0 console.log(result.a.length);  // Outputs: 26 (bypass successful)\n} catch (e) {\n\u00a0 console.log(\u0027Limit enforced:\u0027, e.message);  // Not thrown\n}\n```\n**Configuration:**\n- `comma: true`\n- `arrayLimit: 5`\n- `throwOnLimitExceeded: true`\n\nExpected: Throws \"Array limit exceeded\" error.\nActual: Parses successfully, creating an array of length 26.\n\n\n### Impact\nDenial of Service (DoS) via memory exhaustion."
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However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of arbitrarily large arrays from a single parameter, leading to excessive memory allocation.\\n\\n**Vulnerable code** (lib/parse.js: lines ~40-50):\\n```js\\nif (val \u0026\u0026 typeof val === \u0027string\u0027 \u0026\u0026 options.comma \u0026\u0026 val.indexOf(\u0027,\u0027) \u003e -1) {\\n\u00a0 \u00a0 return val.split(\u0027,\u0027);\\n}\\n\\nif (options.throwOnLimitExceeded \u0026\u0026 currentArrayLength \u003e= options.arrayLimit) {\\n\u00a0 \u00a0 throw new RangeError(\u0027Array limit exceeded. Only \u0027 + options.arrayLimit + \u0027 element\u0027 + (options.arrayLimit === 1 ? \u0027\u0027 : \u0027s\u0027) + \u0027 allowed in an array.\u0027);\\n}\\n\\nreturn val;\\n```\\nThe `split(\u0027,\u0027)` returns the array immediately, skipping the subsequent limit check. Downstream merging via `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`), allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`, which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in v6.14.1 per GHSA-6rw7-vpxm-498p).\\n\\n### PoC\\n**Test 1 - Basic bypass:**\\n```\\nnpm install qs\\n```\\n\\n```js\\nconst qs = require(\u0027qs\u0027);\\n\\nconst payload = \u0027a=\u0027 + \u0027,\u0027.repeat(25);  // 26 elements after split (bypasses arrayLimit: 5)\\nconst options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true };\\n\\ntry {\\n\u00a0 const result = qs.parse(payload, options);\\n\u00a0 console.log(result.a.length);  // Outputs: 26 (bypass successful)\\n} catch (e) {\\n\u00a0 console.log(\u0027Limit enforced:\u0027, e.message);  // Not thrown\\n}\\n```\\n**Configuration:**\\n- `comma: true`\\n- `arrayLimit: 5`\\n- `throwOnLimitExceeded: true`\\n\\nExpected: Throws \\\"Array limit exceeded\\\" error.\\nActual: Parses successfully, creating an array of length 26.\\n\\n\\n### Impact\\nDenial of Service (DoS) via memory exhaustion.\"},{\"lang\":\"es\",\"value\":\"### Resumen\\nLa opci\u00f3n `arrayLimit` en qs no aplica l\u00edmites para valores separados por comas cuando `comma: true` est\u00e1 habilitado, permitiendo a los atacantes causar denegaci\u00f3n de servicio a trav\u00e9s del agotamiento de memoria. Esto es un bypass de la aplicaci\u00f3n del l\u00edmite de array, similar al bypass de notaci\u00f3n de corchetes abordado en GHSA-6rw7-vpxm-498p (CVE-2025-15284).\\n\\n### Detalles\\nCuando la opci\u00f3n `comma` se establece en `true` (no es el valor predeterminado, pero es configurable en las aplicaciones), qs permite analizar cadenas separadas por comas como arrays (por ejemplo, `?param=a,b,c` se convierte en `[\u0027a\u0027, \u0027b\u0027, \u0027c\u0027]`). Sin embargo, la verificaci\u00f3n de l\u00edmite para `arrayLimit` (predeterminado: 20) y la opci\u00f3n throwOnLimitExceeded ocurren despu\u00e9s de la l\u00f3gica de manejo de comas en `parseArrayValue`, lo que permite un bypass. Esto permite la creaci\u00f3n de arrays arbitrariamente grandes a partir de un solo par\u00e1metro, lo que lleva a una asignaci\u00f3n excesiva de memoria.\\n\\nC\u00f3digo vulnerable (lib/parse.js: l\u00edneas ~40-50):\\n```js\\nif (val \u0026amp;\u0026amp; typeof val === \u0027string\u0027 \u0026amp;\u0026amp; options.comma \u0026amp;\u0026amp; val.indexOf(\u0027,\u0027) \u0026gt; -1) {\\n    return val.split(\u0027,\u0027);\\n}\\n\\nif (options.throwOnLimitExceeded \u0026amp;\u0026amp; currentArrayLength \u0026gt;= options.arrayLimit) {\\n    throw new RangeError(\u0027Array limit exceeded. Only \u0027 + options.arrayLimit + \u0027 element\u0027 + (options.arrayLimit === 1 ? \u0027\u0027 : \u0027s\u0027) + \u0027 allowed in an array.\u0027);\\n}\\n\\nreturn val;\\n```\\nEl `split(\u0027,\u0027)` devuelve el array inmediatamente, omitiendo la verificaci\u00f3n de l\u00edmite subsiguiente. La fusi\u00f3n posterior a trav\u00e9s de `utils.combine` no evita la asignaci\u00f3n, incluso si marca desbordamientos para arrays dispersos. Esta discrepancia permite a los atacantes enviar un solo par\u00e1metro con millones de comas (por ejemplo, `?param=,,,,,,,,...`), asignando arrays masivos en memoria sin activar los l\u00edmites. Bypassea la intenci\u00f3n de `arrayLimit`, que se aplica correctamente para las notaciones indexadas (`a[0]=`) y de corchetes (`a[]=`) (esta \u00faltima corregida en v6.14.1 seg\u00fan GHSA-6rw7-vpxm-498p).\\n\\n### PoC\\nPrueba 1 - Bypass b\u00e1sico:\\n```\\nnpm install qs\\n```\\n\\n```js\\nconst qs = require(\u0027qs\u0027);\\n\\nconst payload = \u0027a=\u0027 + \u0027,\u0027.repeat(25);  // 26 elements after split (bypasses arrayLimit: 5)\\nconst options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true };\\n\\ntry {\\n  const result = qs.parse(payload, options);\\n  console.log(result.a.length);  // Outputs: 26 (bypass successful)\\n} catch (e) {\\n  console.log(\u0027Limit enforced:\u0027, e.message);  // Not thrown\\n}\\n```\\nConfiguraci\u00f3n:\\n- `comma: true`\\n- `arrayLimit: 5`\\n- `throwOnLimitExceeded: true`\\n\\nEsperado: Lanza el error \u0027Array limit exceeded\u0027.\\nReal: Analiza con \u00e9xito, creando un array de longitud 26.\\n\\n### Impacto\\nDenegaci\u00f3n de Servicio (DoS) a trav\u00e9s del agotamiento de memoria.\"}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"7ffcee3d-2c14-4c3e-b844-86c6a321a158\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X\",\"baseScore\":6.3,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"PRESENT\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"LOW\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"cvssMetricV31\":[{\"source\":\"7ffcee3d-2c14-4c3e-b844-86c6a321a158\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L\",\"baseScore\":3.7,\"baseSeverity\":\"LOW\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":2.2,\"impactScore\":1.4},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"7ffcee3d-2c14-4c3e-b844-86c6a321a158\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-20\"}]},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"NVD-CWE-noinfo\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:qs_project:qs:*:*:*:*:*:node.js:*:*\",\"versionStartIncluding\":\"6.7.0\",\"versionEndExcluding\":\"6.14.2\",\"matchCriteriaId\":\"94E3C0EE-F451-4D63-8670-0E428FED05AD\"}]}]}],\"references\":[{\"url\":\"https://github.com/ljharb/qs/commit/f6a7abff1f13d644db9b05fe4f2c98ada6bf8482\",\"source\":\"7ffcee3d-2c14-4c3e-b844-86c6a321a158\",\"tags\":[\"Patch\"]},{\"url\":\"https://github.com/ljharb/qs/security/advisories/GHSA-w7fw-mjwx-w883\",\"source\":\"7ffcee3d-2c14-4c3e-b844-86c6a321a158\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]},{\"url\":\"https://github.com/ljharb/qs/security/advisories/GHSA-w7fw-mjwx-w883\",\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-2391\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-02-12T15:00:21.359233Z\"}}}], \"references\": [{\"url\": \"https://github.com/ljharb/qs/security/advisories/GHSA-w7fw-mjwx-w883\", \"tags\": [\"exploit\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-02-12T15:00:12.364Z\"}}], \"cna\": {\"title\": \"qs\u0027s arrayLimit bypass in comma parsing allows denial of service\", \"source\": {\"discovery\": \"UNKNOWN\"}, \"impacts\": [{\"capecId\": \"CAPEC-130\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"CAPEC-130 Excessive Allocation\"}]}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV4_0\": {\"Safety\": \"NOT_DEFINED\", \"version\": \"4.0\", \"Recovery\": \"NOT_DEFINED\", \"baseScore\": 6.3, \"Automatable\": \"NOT_DEFINED\", \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"valueDensity\": \"NOT_DEFINED\", \"vectorString\": \"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N\", \"exploitMaturity\": \"NOT_DEFINED\", \"providerUrgency\": \"NOT_DEFINED\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"attackRequirements\": \"PRESENT\", \"privilegesRequired\": \"NONE\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"NONE\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"LOW\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"NONE\", \"vulnerabilityResponseEffort\": \"NOT_DEFINED\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}, {\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 3.7, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"LOW\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"LOW\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"repo\": \"https://github.com/ljharb/qs\", \"versions\": [{\"status\": \"affected\", \"version\": \"6.7.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.14.1\"}], \"packageName\": \"qs\", \"collectionURL\": \"https://npmjs.com/qs\", \"defaultStatus\": \"unaffected\"}], \"references\": [{\"url\": \"https://github.com/ljharb/qs/security/advisories/GHSA-w7fw-mjwx-w883\", \"tags\": [\"vendor-advisory\"]}, {\"url\": \"https://github.com/ljharb/qs/commit/f6a7abff1f13d644db9b05fe4f2c98ada6bf8482\", \"tags\": [\"patch\"]}], \"x_generator\": {\"engine\": \"Vulnogram 0.5.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"### Summary\\nThe `arrayLimit` option in qs does not enforce limits for comma-separated values when `comma: true` is enabled, allowing attackers to cause denial-of-service via memory exhaustion. This is a bypass of the array limit enforcement, similar to the bracket notation bypass addressed in GHSA-6rw7-vpxm-498p (CVE-2025-15284).\\n\\n### Details\\nWhen the `comma` option is set to `true` (not the default, but configurable in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `[\u0027a\u0027, \u0027b\u0027, \u0027c\u0027]`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of arbitrarily large arrays from a single parameter, leading to excessive memory allocation.\\n\\n**Vulnerable code** (lib/parse.js: lines ~40-50):\\n```js\\nif (val \u0026\u0026 typeof val === \u0027string\u0027 \u0026\u0026 options.comma \u0026\u0026 val.indexOf(\u0027,\u0027) \u003e -1) {\\n\\u00a0 \\u00a0 return val.split(\u0027,\u0027);\\n}\\n\\nif (options.throwOnLimitExceeded \u0026\u0026 currentArrayLength \u003e= options.arrayLimit) {\\n\\u00a0 \\u00a0 throw new RangeError(\u0027Array limit exceeded. Only \u0027 + options.arrayLimit + \u0027 element\u0027 + (options.arrayLimit === 1 ? \u0027\u0027 : \u0027s\u0027) + \u0027 allowed in an array.\u0027);\\n}\\n\\nreturn val;\\n```\\nThe `split(\u0027,\u0027)` returns the array immediately, skipping the subsequent limit check. Downstream merging via `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`), allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`, which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in v6.14.1 per GHSA-6rw7-vpxm-498p).\\n\\n### PoC\\n**Test 1 - Basic bypass:**\\n```\\nnpm install qs\\n```\\n\\n```js\\nconst qs = require(\u0027qs\u0027);\\n\\nconst payload = \u0027a=\u0027 + \u0027,\u0027.repeat(25);  // 26 elements after split (bypasses arrayLimit: 5)\\nconst options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true };\\n\\ntry {\\n\\u00a0 const result = qs.parse(payload, options);\\n\\u00a0 console.log(result.a.length);  // Outputs: 26 (bypass successful)\\n} catch (e) {\\n\\u00a0 console.log(\u0027Limit enforced:\u0027, e.message);  // Not thrown\\n}\\n```\\n**Configuration:**\\n- `comma: true`\\n- `arrayLimit: 5`\\n- `throwOnLimitExceeded: true`\\n\\nExpected: Throws \\\"Array limit exceeded\\\" error.\\nActual: Parses successfully, creating an array of length 26.\\n\\n\\n### Impact\\nDenial of Service (DoS) via memory exhaustion.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"### Summary\u003cbr\u003eThe `arrayLimit` option in qs does not enforce limits for comma-separated values when `comma: true` is enabled, allowing attackers to cause denial-of-service via memory exhaustion. This is a bypass of the array limit enforcement, similar to the bracket notation bypass addressed in GHSA-6rw7-vpxm-498p (CVE-2025-15284).\u003cbr\u003e\u003cbr\u003e### Details\u003cbr\u003eWhen the `comma` option is set to `true` (not the default, but configurable in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `[\u0027a\u0027, \u0027b\u0027, \u0027c\u0027]`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of arbitrarily large arrays from a single parameter, leading to excessive memory allocation.\u003cbr\u003e\u003cbr\u003e**Vulnerable code** (lib/parse.js: lines ~40-50):\u003cbr\u003e```js\u003cbr\u003eif (val \u0026amp;\u0026amp; typeof val === \u0027string\u0027 \u0026amp;\u0026amp; options.comma \u0026amp;\u0026amp; val.indexOf(\u0027,\u0027) \u0026gt; -1) {\u003cbr\u003e\u0026nbsp; \u0026nbsp; return val.split(\u0027,\u0027);\u003cbr\u003e}\u003cbr\u003e\u003cbr\u003eif (options.throwOnLimitExceeded \u0026amp;\u0026amp; currentArrayLength \u0026gt;= options.arrayLimit) {\u003cbr\u003e\u0026nbsp; \u0026nbsp; throw new RangeError(\u0027Array limit exceeded. Only \u0027 + options.arrayLimit + \u0027 element\u0027 + (options.arrayLimit === 1 ? \u0027\u0027 : \u0027s\u0027) + \u0027 allowed in an array.\u0027);\u003cbr\u003e}\u003cbr\u003e\u003cbr\u003ereturn val;\u003cbr\u003e```\u003cbr\u003eThe `split(\u0027,\u0027)` returns the array immediately, skipping the subsequent limit check. Downstream merging via `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`), allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`, which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in v6.14.1 per GHSA-6rw7-vpxm-498p).\u003cbr\u003e\u003cbr\u003e### PoC\u003cbr\u003e**Test 1 - Basic bypass:**\u003cbr\u003e```\u003cbr\u003enpm install qs\u003cbr\u003e```\u003cbr\u003e\u003cbr\u003e```js\u003cbr\u003econst qs = require(\u0027qs\u0027);\u003cbr\u003e\u003cbr\u003econst payload = \u0027a=\u0027 + \u0027,\u0027.repeat(25);  // 26 elements after split (bypasses arrayLimit: 5)\u003cbr\u003econst options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true };\u003cbr\u003e\u003cbr\u003etry {\u003cbr\u003e\u0026nbsp; const result = qs.parse(payload, options);\u003cbr\u003e\u0026nbsp; console.log(result.a.length);  // Outputs: 26 (bypass successful)\u003cbr\u003e} catch (e) {\u003cbr\u003e\u0026nbsp; console.log(\u0027Limit enforced:\u0027, e.message);  // Not thrown\u003cbr\u003e}\u003cbr\u003e```\u003cbr\u003e**Configuration:**\u003cbr\u003e- `comma: true`\u003cbr\u003e- `arrayLimit: 5`\u003cbr\u003e- `throwOnLimitExceeded: true`\u003cbr\u003e\u003cbr\u003eExpected: Throws \\\"Array limit exceeded\\\" error.\u003cbr\u003eActual: Parses successfully, creating an array of length 26.\u003cbr\u003e\u003cbr\u003e\u003cbr\u003e### Impact\u003cbr\u003eDenial of Service (DoS) via memory exhaustion.\u003cbr\u003e\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-20\", \"description\": \"CWE-20 Improper Input Validation\"}]}], \"providerMetadata\": {\"orgId\": \"7ffcee3d-2c14-4c3e-b844-86c6a321a158\", \"shortName\": \"harborist\", \"dateUpdated\": \"2026-02-12T17:32:05.953Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-2391\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-02-12T17:32:05.953Z\", \"dateReserved\": \"2026-02-12T03:52:09.332Z\", \"assignerOrgId\": \"7ffcee3d-2c14-4c3e-b844-86c6a321a158\", \"datePublished\": \"2026-02-12T04:39:42.914Z\", \"assignerShortName\": \"harborist\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.