--- id: CVE-2026-82562 title: >- ### Summary When `qs.parse` is called with `comma: true` and `throwOnLimitExceeded: true`, a comma-separated value under a bracket-push key (`a[]=1,2,3,4`) is split into an array without being compared against `arrayLimit`, while the … summary: >- ### Summary When `qs.parse` is called with `comma: true` and `throwOnLimitExceeded: true`, a comma-separated value under a bracket-push key (`a[]=1,2,3,4`) is split into an array without being compared against `arrayLimit`, while the … severity: low cvss: 3.7 cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L' cwe: - CWE-770 published: '2026-08-30' updated: '2026-08-30' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82562' references: - url: >- https://github.com/ljharb/qs/commit/8859c37470e11b42b547b275e4e9bd0bc8cc5464 label: 7ffcee3d-2c14-4c3e-b844-86c6a321a158 - url: 'https://github.com/ljharb/qs/security/advisories/GHSA-w7fw-mjwx-w883' label: 7ffcee3d-2c14-4c3e-b844-86c6a321a158 - url: 'https://github.com/ljharb/qs/security/advisories/GHSA-x5fp-wj9c-mxmx' label: 7ffcee3d-2c14-4c3e-b844-86c6a321a158 - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-82562.json - url: 'https://access.redhat.com/security/cve/CVE-2026-82562' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2525939' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-82562' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82562' - url: 'https://access.redhat.com/errata/RHSA-2026:60866' - url: 'https://access.redhat.com/errata/RHSA-2026:62544' - url: 'https://access.redhat.com/errata/RHSA-2026:63164' - url: 'https://access.redhat.com/errata/RHSA-2026:68754' tags: - nvd - csaf - vex - red-hat epss: 0.0054 epssPercentile: 0.43045 ingestedAt: '2026-08-30T14:53:42.577Z' vendor: Red Hat product: Red Hat Enterprise Linux 9 affected: - cost_management_on_premise - cryostat 4 - gatekeeper 3 - migration_toolkit_for_applications 8 - migration_toolkit_for_containers - multicluster_engine_for_kubernetes - node_healthcheck_operator - openshift_lightspeed - openshift_pipelines - openshift_serverless - openshift_service_mesh 3 - 3scale_api_management_platform 2 - advanced_cluster_management_for_kubernetes 2 - advanced_cluster_security 4 - amq_broker 7 - ansible_automation_platform 2 - build_of_apache_camel_for_spring_boot 4 - build_of_podman_desktop - ceph_storage 4 - ceph_storage 6 - ceph_storage 7 - ceph_storage 8 - ceph_storage 9 - connectivity_link 1 - data_grid 8 - developer_hub - discovery 2 - enterprise_linux 10 - enterprise_linux 7 - enterprise_linux 8 - enterprise_linux 9 - enterprise_linux_ai_rhel_ai 3 - fuse 7 - hardened_images - jboss_enterprise_application_platform 7 - openshift_ai_rhoai - openshift_container_platform 4 - openshift_data_foundation 4 - openshift_dev_spaces - openshift_gitops patched: - hardened_images --- ## Overview ### Summary When `qs.parse` is called with `comma: true` and `throwOnLimitExceeded: true`, a comma-separated value under a bracket-push key (`a[]=1,2,3,4`) is split into an array without being compared against `arrayLimit`, while the same value under a flat key (`a=1,2,3,4`), an indexed key (`a[0]=`), a nested key (`a[b]=`), or a dotted key (`a.b=` with `allowDots`) throws the documented `RangeError`. A single parameter such as `a[]=1,2,2,...` therefore produces an inner array of arbitrary length even though the caller opted into the hard limit. This is the `[]=` key form that the fix for CVE-2026-2391 (qs 6.14.2) did not cover. ### Details In `lib/parse.js`, a comma-separated value under a `[]=` key is split and then wrapped as a single nested element (`val = [val]`, so that each `a[]=x,y` group counts as one element of the outer array). The `arrayLimit` check that 6.14.2 added for comma values runs after that wrap, so for `[]=` parts it only ever saw the wrapper of length 1. 6.15.3 added a pre-split comma count so that an oversized value throws before it is allocated, but gated it on an `isFlatArrayValue` flag that `parseValues` set to `false` for any part containing `[]=`, and did not pass it for object-valued input, so the gap remained. #### PoC ```js var qs = require('qs'); var options = { comma: true, arrayLimit: 3, throwOnLimitExceeded: true }; qs.parse('a=1,2,3,4', options); // RangeError: Array limit exceeded. Only 3 elements allowed in an array. qs.parse('a[]=1,2,3,4', options); // { a: [ [ '1', '2', '3', '4' ] ] } (no throw) qs.parse('a[]=' + '1,'.repeat(1000000) + '1', { comma: true, arrayLimit: 20, throwOnLimitExceeded: true }); // no throw; a 1,000,001-element inner array is allocated ``` #### Fix `lib/parse.js`, applied in 8859c37 on `main` and released as v6.16.0: the `isFlatArrayValue` gate is removed, so every comma-split value is counted against `arrayLimit` before splitting regardless of key form. An in-limit group under `a[]=` still counts as one element of the outer array, and the default (`throwOnLimitExceeded: false`) path is unchanged. ### Affected versions `>=6.14.2 <6.16.0`, fixed in v6.16.0. v6.14.2 introduced `arrayLimit` enforcement for comma values (the fix for CVE-2026-2391) but only for values not under a `[]=` key, and every release from v6.14.2 through v6.15.3 has the same gap. v6.14.0 and v6.14.1, where `throwOnLimitExceeded` exists but does not apply to any comma form, are covered by CVE-2026-2391 rather than this record. Earlier lines (6.7.x through 6.13.x) have `comma` but no `throwOnLimitExceeded`, so there is no hard cap on any comma path to bypass; releases before 6.7.0 have no `comma` option. ### Impact An unauthenticated attacker who can reach an application that parses untrusted query strings or urlencoded bodies with both `comma: true` and `throwOnLimitExceeded: true` (both non-default) can bypass the configured limit with a single `a[]=` parameter and force the parser to allocate an array proportional to the request size. The cost is strictly linear in the attacker-supplied bytes (about 0.1 microseconds and 6 to 7 retained bytes per input byte; the same out-of-memory threshold as the documented default `throwOnLimitExceeded: false` path), so a transport-layer request or body size limit bounds it completely (and node's default maximum HTTP header size of 16 KB already bounds the request line, so multi-megabyte payloads need a body parser). The impact is that an opt-in hard limit fails open on one key spelling, not unbounded allocation from a small input. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:60866** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-29 · [advisory](https://access.redhat.com/errata/RHSA-2026:60866) - **RHSA-2026:62544** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:62544) - **RHSA-2026:63164** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63164) - **Red Hat VEX** · Low · affected: Ansible Automation Orchestrator 2026, Cost Management On Premise, Cryostat 4, Gatekeeper 3, Migration Toolkit for Applications 8, Migration Toolkit for Containers, … · no fix planned: Node HealthCheck Operator, OpenShift Service Mesh 3, Red Hat 3scale API Management Platform 2, Red Hat Advanced Cluster Management for Kubernetes 2, … · updated 2026-09-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-82562.json) - **RHSA-2026:68754** · Red Hat · fixed in: Red Hat OpenShift Dev Spaces 3.30 · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68754)