Skip to content

Conversation

@renovate
Copy link
Contributor

@renovate renovate bot commented Jan 1, 2026

This PR contains the following updates:

Package Change Age Confidence
qs 6.13.06.14.1 age confidence

GitHub Vulnerability Alerts

CVE-2025-15284

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[]=value consumes 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.


Release Notes

ljharb/qs (qs)

v6.14.1

Compare Source

  • [Fix] ensure arrayLength applies to [] notation as well
  • [Fix] parse: when a custom decoder returns null for a key, ignore that key
  • [Refactor] parse: extract key segment splitting helper
  • [meta] add threat model
  • [actions] add workflow permissions
  • [Tests] stringify: increase coverage
  • [Dev Deps] update eslint, @ljharb/eslint-config, npmignore, es-value-fixtures, for-each, object-inspect

v6.14.0

Compare Source

  • [New] parse: add throwOnParameterLimitExceeded option (#​517)
  • [Refactor] parse: use utils.combine more
  • [patch] parse: add explicit throwOnLimitExceeded default
  • [actions] use shared action; re-add finishers
  • [meta] Fix changelog formatting bug
  • [Deps] update side-channel
  • [Dev Deps] update es-value-fixtures, has-bigints, has-proto, has-symbols
  • [Tests] increase coverage

v6.13.1

Compare Source

  • [Fix] stringify: avoid a crash when a filter key is null
  • [Fix] utils.merge: functions should not be stringified into keys
  • [Fix] parse: avoid a crash with interpretNumericEntities: true, comma: true, and iso charset
  • [Fix] stringify: ensure a non-string filter does not crash
  • [Refactor] use __proto__ syntax instead of Object.create for null objects
  • [Refactor] misc cleanup
  • [Tests] utils.merge: add some coverage
  • [Tests] fix a test case
  • [actions] split out node 10-20, and 20+
  • [Dev Deps] update es-value-fixtures, mock-property, object-inspect, tape

Configuration

📅 Schedule: Branch creation - "" (UTC), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

0 participants