body-parser-1.20.3.tgz: 4 vulnerabilities (highest severity is: 5.3)

[mend-for-github-com]

Vulnerable Library - body-parser-1.20.3.tgz

Node.js body parsing middleware

Library home page: https://registry.npmjs.org/body-parser/-/body-parser-1.20.3.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/body-parser/package.json

Vulnerabilities

Vulnerability	Severity	CVSS	Exploit Maturity	EPSS	Dependency	Type	Fixed in (body-parser version)	Remediation Possible**	Reachability
CVE-2026-8723	Medium	5.3	Not Defined	0.351%	qs-6.13.0.tgz	Transitive	1.20.5	✅
CVE-2026-2391	Low	3.7	Not Defined	0.478%	qs-6.13.0.tgz	Transitive	1.20.4	✅
CVE-2026-12590	Low	3.7	Not Defined	0.25%	body-parser-1.20.3.tgz	Direct	1.20.6	✅
CVE-2025-15284	Low	3.7	Not Defined	0.41%	qs-6.13.0.tgz	Transitive	1.20.4	✅

**In some cases, Remediation PR cannot be created automatically for a vulnerability despite the availability of remediation

Details

CVE-2026-8723

Vulnerable Library - qs-6.13.0.tgz

Library home page: https://registry.npmjs.org/qs/-/qs-6.13.0.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/qs/package.json

Dependency Hierarchy:

• body-parser-1.20.3.tgz (Root Library)
  • ❌ qs-6.13.0.tgz (Vulnerable Library)

Found in base branch: main

Vulnerability Details

Summary
"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").
Details
In the comma + "encodeValuesOnly" branch, "lib/stringify.js:145" mapped the array through the raw encoder before joining:
obj = utils.maybeMap(obj, encoder);
"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.
Same 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.
PoC
const qs = require('qs');
qs.stringify({ a: [null, 'b'] }, { arrayFormat: 'comma', encodeValuesOnly: true });
qs.stringify({ a: [undefined, 'b'] }, { arrayFormat: 'comma', encodeValuesOnly: true });
qs.stringify({ a: [null] }, { arrayFormat: 'comma', encodeValuesOnly: true });
// TypeError: Cannot read properties of null (reading 'length')
// at encode (lib/utils.js:195:13)
// at Object.maybeMap (lib/utils.js:322:37)
// at stringify (lib/stringify.js:145:25)
Fix
"lib/stringify.js:145", applied in 21f80b3 on "main" and released as v6.15.2:

• obj = utils.maybeMap(obj, encoder);

• obj = utils.maybeMap(obj, function (v) {

• return v == null ? v : encoder(v);
  

• });
  "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.
  Affected versions
  ">=6.11.1 <6.15.2" — fixed in v6.15.2.
  The 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.
  Impact
  Application 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.
  The 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").
  Mend Note: The description of this vulnerability differs from MITRE.

Publish Date: 2026-05-16

URL: CVE-2026-8723

Threat Assessment

Exploit Maturity: Not Defined

EPSS: 0.351%

CVSS 3 Score Details (5.3)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: Low
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: None
  • Integrity Impact: None
  • Availability Impact: Low

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Origin: GHSA-q8mj-m7cp-5q26

Release Date: 2026-05-16

Fix Resolution (qs): 6.15.2

Direct dependency fix Resolution (body-parser): 1.20.5

⛑️ Automatic Remediation will be attempted for this issue.

CVE-2026-2391

Vulnerable Library - qs-6.13.0.tgz

Library home page: https://registry.npmjs.org/qs/-/qs-6.13.0.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/qs/package.json

Dependency Hierarchy:

• body-parser-1.20.3.tgz (Root Library)
  • ❌ qs-6.13.0.tgz (Vulnerable Library)

Found in base branch: main

Vulnerability Details

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):
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
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.
  Mend Note: The description of this vulnerability differs from MITRE.

Publish Date: 2026-02-12

URL: CVE-2026-2391

Threat Assessment

Exploit Maturity: Not Defined

EPSS: 0.478%

CVSS 3 Score Details (3.7)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: High
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: None
  • Integrity Impact: None
  • Availability Impact: Low

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Origin: GHSA-w7fw-mjwx-w883

Release Date: 2026-02-12

Fix Resolution (qs): 6.14.2

Direct dependency fix Resolution (body-parser): 1.20.4

⛑️ Automatic Remediation will be attempted for this issue.

CVE-2026-12590

Vulnerable Library - body-parser-1.20.3.tgz

Node.js body parsing middleware

Library home page: https://registry.npmjs.org/body-parser/-/body-parser-1.20.3.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/body-parser/package.json

Dependency Hierarchy:

• ❌ body-parser-1.20.3.tgz (Vulnerable Library)

Found in base branch: main

Vulnerability Details

Impact: In body-parser versions prior to 1.20.6 (1.x line) and 2.3.0 (2.x line), when the parser is configured with an invalid limit option value such as an unparseable string or NaN, bytes.parse returns null and the request body size check is silently skipped. Applications that rely on limit as their primary safeguard against oversized request bodies will accept arbitrarily large payloads, leading to excessive memory and CPU usage and denial of service. Patches: This issue is fixed in body-parser 1.20.6 and 2.3.0. After the fix, invalid limit values throw a clear error at parser construction time instead of silently disabling enforcement, while null and undefined continue to fall back to the default limit of 100kb. Workarounds: Validate the limit value before passing it to body-parser. For example, parse the value at startup and reject any configuration where the result is null or a non-finite number.

Publish Date: 2026-07-09

URL: CVE-2026-12590

Threat Assessment

Exploit Maturity: Not Defined

EPSS: 0.25%

CVSS 3 Score Details (3.7)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: High
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: None
  • Integrity Impact: None
  • Availability Impact: Low

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Origin: GHSA-v422-hmwv-36x6

Release Date: 2026-07-09

Fix Resolution: 1.20.6

⛑️ Automatic Remediation will be attempted for this issue.

CVE-2025-15284

Vulnerable Library - qs-6.13.0.tgz

Library home page: https://registry.npmjs.org/qs/-/qs-6.13.0.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/qs/package.json

Dependency Hierarchy:

• body-parser-1.20.3.tgz (Root Library)
  • ❌ qs-6.13.0.tgz (Vulnerable Library)

Found in base branch: main

Vulnerability Details

Improper Input Validation vulnerability in qs (parse modules) allows HTTP DoS.This issue affects qs: < 6.14.1.
Summary
The arrayLimit option in qs did not enforce limits for bracket notation (a[]=1&a[]=2), only for indexed notation (a[0]=1). This is a consistency bug; arrayLimit should apply uniformly across all array notations.
Note: The default parameterLimit of 1000 effectively mitigates the DoS scenario originally described. With default options, bracket notation cannot produce arrays larger than parameterLimit regardless of arrayLimit, because each a[]=valueconsumes one parameter slot. The severity has been reduced accordingly.
Details
The arrayLimit option only checked limits for indexed notation (a[0]=1&a[1]=2) but did not enforce it for bracket notation (a[]=1&a[]=2).
Vulnerable code (lib/parse.js:159-162):
if (root === '[]' && options.parseArrays) {
obj = utils.combine([], leaf); // No arrayLimit check
}
Working code (lib/parse.js:175):
else if (index <= options.arrayLimit) { // Limit checked here
obj = [];
obj[index] = leaf;
}
The bracket notation handler at line 159 uses utils.combine([], leaf) without validating against options.arrayLimit, while indexed notation at line 175 checks index <= options.arrayLimit before creating arrays.
PoC
const qs = require('qs');
const result = qs.parse('a[]=1&a[]=2&a[]=3&a[]=4&a[]=5&a[]=6', { arrayLimit: 5 });
console.log(result.a.length); // Output: 6 (should be max 5)
Note on parameterLimit interaction: The original advisory's "DoS demonstration" claimed a length of 10,000, but parameterLimit (default: 1000) caps parsing to 1,000 parameters. With default options, the actual output is 1,000, not 10,000.
Impact
Consistency bug in arrayLimit enforcement. With default parameterLimit, the practical DoS risk is negligible since parameterLimit already caps the total number of parsed parameters (and thus array elements from bracket notation). The risk increases only when parameterLimit is explicitly set to a very high value.

Publish Date: 2025-12-29

URL: CVE-2025-15284

Threat Assessment

Exploit Maturity: Not Defined

EPSS: 0.41%

CVSS 3 Score Details (3.7)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: High
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: None
  • Integrity Impact: None
  • Availability Impact: Low

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Origin: GHSA-6rw7-vpxm-498p

Release Date: 2025-12-29

Fix Resolution (qs): 6.14.1

Direct dependency fix Resolution (body-parser): 1.20.4

⛑️ Automatic Remediation will be attempted for this issue.

---

⛑️Automatic Remediation will be attempted for this issue.

[mend-for-github-com]

✔️ This issue was automatically closed by Mend because the vulnerable library in the specific branch(es) was either marked as ignored or it is no longer part of the Mend inventory.

[mend-for-github-com]

ℹ️ This issue was automatically re-opened by Mend because the vulnerable library in the specific branch(es) has been detected in the Mend inventory.