Update dependency qs to v6.16.0 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
qs	6.15.2 → 6.16.0

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qs array-limit bypass via bracket-key comma parsing

CVE-2026-82562 / GHSA-x5fp-wj9c-mxmx

More information

Details

Summary

qs v6.15.3 allows bracket-key input to bypass arrayLimit and throwOnLimitExceeded when comma: true. The input a[]=1,2,3,4 succeeds with arrayLimit: 3, while the equivalent plain-key input is rejected.

Affected version tested:

qs v6.15.3
commit 18d085e919dae70c8f1b200ab99323058edab2c2

Details

parseArrayValue() enforces the comma limit only for flat values. The a[] form is marked non-flat, so its comma-separated value is wrapped after parsing and the inner array is not checked. A single parameter can therefore materialize arbitrarily large arrays.

PoC

const qs = require('qs')
const options = { comma: true, arrayLimit: 3, throwOnLimitExceeded: true }

const result = qs.parse('a[]=1,2,3,4', options)
console.log(result.a[0].length) // 4; expected RangeError

const big = qs.parse('a[]=' + '1,'.repeat(1000000) + '1', { comma: true, arrayLimit: 20 })
console.log(big.a[0].length) // 1000001

On v6.15.3, the first input parses successfully and the second creates an array with 1,000,001 elements. The equivalent a=1,2,3,4 input throws RangeError as expected.

Impact

An attacker who can supply a query string or form body can bypass configured array limits and force excessive memory allocation, causing denial of service. The limit must be applied after comma splitting and before the resulting array is wrapped.

Severity

• CVSS Score: 6.3 / 10 (Medium)
• Vector String: 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

References

• https://github.com/ljharb/qs/security/advisories/GHSA-w7fw-mjwx-w883
• https://github.com/ljharb/qs/security/advisories/GHSA-x5fp-wj9c-mxmx
• https://nvd.nist.gov/vuln/detail/CVE-2026-82562
• https://github.com/ljharb/qs/commit/8859c37470e11b42b547b275e4e9bd0bc8cc5464
• https://github.com/advisories/GHSA-x5fp-wj9c-mxmx

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

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Release Notes

ljharb/qs (qs)

v6.16.0

Compare Source

• [New] stringify: add a depth option to bound recursion depth (default Infinity)
• [Fix] stringify: serialize Date values when a filter is provided
• [Fix] parse: enforce arrayLimit on comma groups under []= when throwOnLimitExceeded is set
• [Fix] parse: flatten a collection appended to an overflowed array (#​571)
• [Fix] utils: isBuffer: do not invoke a non-callable constructor.isBuffer
• [Fix] stringify: do not let allowEmptyArrays skip cycle detection (or drop own keys) on an empty array with own properties
• [Fix] stringify: encode dots in a top-level key with a primitive value when encodeDotInKeys is set (#​562)
• [Docs] threat model: clarify stringify deep-nesting DoS is caller-bounded
• [Docs] clarify arrayLimit is a representation threshold, not an element-count cap
• [Tests] parse: remove a test that pinned []= comma groups escaping arrayLimit
• [Tests] stringify: pin current encodeDotInKeys separator-dot behavior
• [Dev Deps] update @ljharb/eslint-config, eslint
• [Dev Deps] update eslint, evalmd

v6.15.3

Compare Source

• [Fix] parse: enforce throwOnLimitExceeded for cumulative array growth via combine/merge
• [Fix] utils: respect encoding of surrogate pairs across chunks (#​559)
• [Robustness] parse: throw the arrayLimit error before splitting oversized comma values
• [Robustness] utils.merge / utils.assign: avoid invoking __proto__ setter when copying own properties
• [Robustness] utils: enforce arrayLimit consistently across merge's array paths
• [Perf] utils: make compact O(n) via a side-channel visited-set instead of Array.indexOf
• [Deps] update side-channel
• [Dev Deps] update eslint, mock-property, tape
• [Tests] parse: characterize current lenient handling of unbalanced bracket keys (#​558)

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