chore(deps): update dependency qs@<6.14.1 to >=6.15.1 [security]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
qs@<6.14.1	>=6.14.1 → >=6.15.1

---

qs's arrayLimit bypass in comma parsing allows denial of service

CVE-2026-2391 / GHSA-w7fw-mjwx-w883

More information

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.

Suggested Fix

Move the arrayLimit check before the comma split in parseArrayValue, and enforce it on the resulting array length. Use currentArrayLength (already calculated upstream) for consistency with bracket notation fixes.

Current 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;

Fixed code:

if (val && typeof val === 'string' && options.comma && val.indexOf(',') > -1) {
    const splitArray = val.split(',');
    if (splitArray.length > options.arrayLimit - currentArrayLength) {  // Check against remaining limit
        if (options.throwOnLimitExceeded) {
            throw new RangeError('Array limit exceeded. Only ' + options.arrayLimit + ' element' + (options.arrayLimit === 1 ? '' : 's') + ' allowed in an array.');
        } else {
            // Optionally convert to object or truncate, per README
            return splitArray.slice(0, options.arrayLimit - currentArrayLength);
        }
    }
    return splitArray;
}

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;

This aligns behavior with indexed and bracket notations, reuses currentArrayLength, and respects throwOnLimitExceeded. Update README to note the consistent enforcement.

Severity

• CVSS Score: 3.7 / 10 (Low)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

References

• https://github.com/ljharb/qs/security/advisories/GHSA-w7fw-mjwx-w883
• https://nvd.nist.gov/vuln/detail/CVE-2026-2391
• https://github.com/ljharb/qs/commit/f6a7abff1f13d644db9b05fe4f2c98ada6bf8482
• https://github.com/advisories/GHSA-w7fw-mjwx-w883

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Release Notes

ljharb/qs (qs@<6.14.1)

v6.15.1

Compare Source

• [Fix] parse: parameterLimit: Infinity with throwOnLimitExceeded: true silently drops all parameters
• [Deps] update @ljharb/eslint-config
• [Dev Deps] update @ljharb/eslint-config, iconv-lite
• [Tests] increase coverage

v6.15.0

Compare Source

• [New] parse: add strictMerge option to wrap object/primitive conflicts in an array (#​425, #​122)
• [Fix] duplicates option should not apply to bracket notation keys (#​514)

v6.14.2

Compare Source

• [Fix] parse: mark overflow objects for indexed notation exceeding arrayLimit (#​546)
• [Fix] arrayLimit means max count, not max index, in combine/merge/parseArrayValue
• [Fix] parse: throw on arrayLimit exceeded with indexed notation when throwOnLimitExceeded is true (#​529)
• [Fix] parse: enforce arrayLimit on comma-parsed values
• [Fix] parse: fix error message to reflect arrayLimit as max index; remove extraneous comments (#​545)
• [Robustness] avoid .push, use void
• [readme] document that addQueryPrefix does not add ? to empty output (#​418)
• [readme] clarify parseArrays and arrayLimit documentation (#​543)
• [readme] replace runkit CI badge with shields.io check-runs badge
• [meta] fix changelog typo (arrayLength → arrayLimit)
• [actions] fix rebase workflow permissions

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🚀 Performance Test Results

Test Configuration:

• VUs: 4
• Duration: 1m0s

Test Metrics:

• Requests/s: 49.03
• Iterations/s: 16.37
• Failed Requests: 0.00% (0 of 2950)

📜 Logs

> performance@1.0.0 run-tests:testenv /home/runner/work/rafiki/rafiki/test/performance
> ./scripts/run-tests.sh -e test -k -q --vus 4 --duration 1m

Cloud Nine GraphQL API is up: http://localhost:3101/graphql
Cloud Nine Wallet Address is up: http://localhost:3100/
Happy Life Bank Address is up: http://localhost:4100/
cloud-nine-wallet-test-backend already set
cloud-nine-wallet-test-auth already set
happy-life-bank-test-backend already set
happy-life-bank-test-auth already set
     data_received..................: 1.1 MB 18 kB/s
     data_sent......................: 2.3 MB 38 kB/s
     http_req_blocked...............: avg=8.04µs   min=2.41µs   med=5.44µs   max=1.43ms   p(90)=6.78µs   p(95)=7.55µs  
     http_req_connecting............: avg=436ns    min=0s       med=0s       max=746.26µs p(90)=0s       p(95)=0s      
     http_req_duration..............: avg=80.94ms  min=6.63ms   med=66.79ms  max=408.68ms p(90)=136.22ms p(95)=158.34ms
       { expected_response:true }...: avg=80.94ms  min=6.63ms   med=66.79ms  max=408.68ms p(90)=136.22ms p(95)=158.34ms
     http_req_failed................: 0.00%  ✓ 0         ✗ 2950
     http_req_receiving.............: avg=86.27µs  min=27.82µs  med=78.13µs  max=1.19ms   p(90)=112.47µs p(95)=133.85µs
     http_req_sending...............: avg=36.03µs  min=9.5µs    med=28.22µs  max=2.13ms   p(90)=40.44µs  p(95)=54.79µs 
     http_req_tls_handshaking.......: avg=0s       min=0s       med=0s       max=0s       p(90)=0s       p(95)=0s      
     http_req_waiting...............: avg=80.82ms  min=6.5ms    med=66.68ms  max=408.6ms  p(90)=136.04ms p(95)=158.13ms
     http_reqs......................: 2950   49.03029/s
     iteration_duration.............: avg=244.06ms min=160.86ms med=231.27ms max=865.75ms p(90)=307.38ms p(95)=341.47ms
     iterations.....................: 985    16.371131/s
     vus............................: 4      min=4       max=4 
     vus_max........................: 4      min=4       max=4