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low 3.7

CVE-2026-82562 json

qs.parse does not enforce arrayLimit on comma groups under bracket-push keys when throwOnLimitExceeded is set (incomplete fix for CVE-2026-2391)

published 2mo ago modified 2mo ago also EUVD-2026-68141 , GHSA-x5fp-wj9c-mxmx

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

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 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.

Patch / fix

  • npm qs 6.16.0
  • ljharb qs 6.16.0
  • node-qs Debian 14 6.16.0+ds+~6.15.1-1

debian advisories DEBIAN-CVE-2026-82562

  • grafana13.1 hummingbird 1 13.1.3-0.4.hum1
  • grafana13.2 hummingbird 1 13.2.1-0.1.hum1
  • grafana12.4 hummingbird 1 12.4.9-0.4.hum1

red hat advisories RHSA-2026:62544RHSA-2026:63164RHSA-2026:60866

Is CVE-2026-82562 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-82562 updated cvss 3.7

qs: qs: Denial of Service via array limit bypass in query string parsing

  • Red Hat Ansible Automation Orchestrator 2026 ansible-automation-platform/automation-orchestrator-ui-rhel9 Red Hat Cost Management On Premise costmanagement/costmanagement-ui-rhel10 Red Hat Cryostat 4 cryostat/cryostat-openshift-console-plugin-rhel9 Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-ui-rhel9, mta/mta-solution-server-rhel9 Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-ui-rhel8
    +1 more products
    Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Node HealthCheck Operator workload-availability/node-remediation-console-rhel8, workload-availability/node-healthcheck-rhel9-operator, workload-availability/node-healthcheck-operator-bundle, workload-availability/node-healthcheck-must-gather-rhel9
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-console-plugin-rhel9, openshift-lightspeed/lightspeed-agentic-console-rhel9, openshift-lightspeed/lightspeed-console-plugin-419-rhel9, openshift-lightspeed/lightspeed-console-plugin-pf5-rhel9 Red Hat OpenShift Pipelines openshift-pipelines/pipelines-hub-ui-rhel8, openshift-pipelines/pipelines-hub-ui-rhel9, openshift-pipelines/pipelines-console-plugin-rhel8, openshift-pipelines/pipelines-console-plugin-rhel9, openshift-pipelines/pipelines-console-plugin-pf5-rhel9 Red Hat OpenShift Serverless openshift-serverless-1/kn-eventing-integrations-log-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-s3-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sns-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sqs-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-timer-source-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-s3-source-rhel9, +3 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9-operator, openshift-service-mesh/kiali-operator-bundle Red Hat 3scale API Management Platform 2 3scale-amp2/system-rhel8
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9, rhacm2/volsync-rhel9, rhacm2/volsync-operator-bundle Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-main-rhel9
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat AMQ Broker 7 amq-broker-bin.zip 7.14.1.CR2, amq-broker-maven-repository.zip 7.14.1.CR3
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ansible Automation Platform 2 automation-controller 4.5.35-1.el9ap, automation-platform-ui 2.6.13-1.el9ap, automation-gateway 2.5.20260824-1.el8ap, ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-25/lightspeed-rhel8, ansible-automation-platform-26/lightspeed-rhel9, +3 more
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat build of Apache Camel for Spring Boot 4 rhaf-camel-maven-repository.zip 4.18.3.ER2, rhaf-camel-spring-boot-maven-repository.zip 4.18.1.CS4, rhaf-camel-for-springboot-maven-repository.zip 3.5.16.CS2 Red Hat Build of Podman Desktop rh-podman-desktop.git 1.1.0
    affected: workaround, no fix available “Fix deferred”
show 9 more
  • Red Hat Ceph Storage 4 cockpit-ceph-installer, rhceph/rhceph-4-dashboard-rhel8 Red Hat Ceph Storage 6 ceph, cephadm, librbd1, librgw2, rbd-nbd, ceph-mib, +16 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Ceph Storage 7 ceph, cephadm, librbd1, librgw2, rbd-nbd, ceph-mib, +16 more Red Hat Ceph Storage 8 ceph, cephadm, librbd1, librgw2, rbd-nbd, ceph-mib, +17 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ceph Storage 9 ceph, cephadm, librbd1, librgw2, rbd-nbd, ceph-mib, +17 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9 Red Hat Data Grid 8 redhat-datagrid-maven-repository.zip 8.6.1.CR1 Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9, rhdh/red-hat-developer-hub-backstage-plugin-lightspeed, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator, rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-form-widgets, +2 more Red Hat Discovery 2 discovery/discovery-ui-rhel9 Red Hat Enterprise Linux 7 rhsm-gtk, python-syspurpose, subscription-manager, subscription-manager-gui, subscription-manager-rhsm, subscription-manager-cockpit, +5 more Red Hat Enterprise Linux 8 pcs, grafana, mozjs60, pcs-snmp, grafana-pcp, grafana-loki, +15 more
    +3 more products
    Red Hat Enterprise Linux 9 npm, pcs, nodejs, grafana, sgx-mpa, tdx-qgs, +36 more Red Hat Enterprise Linux 10 ceph, pcs 0.12.3-2.el10, linux-sgx 2.26-7.el10, nodejs26 26.1.0-1.el10, grafana-pcp 6.1.0-1.el10, nodejs22 22.23.1-3.el10_0, +2 more Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/disk-image-cuda-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Fuse 7 qs 6.5.1
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Hardened Images nodejs25 25.9.0-1.6.hum1, nodejs20 20.20.2-1.2.hum1
    affected: workaround, no fix available “Fix deferred”
  • Red Hat JBoss Enterprise Application Platform 7 jboss-eap-patch.zip 7.4.23, jboss-eap-maven-repository.zip 7.4.23, jboss-eap-runtime-maven-repository.zip 7.4.24, jboss-eap-full-maven-repository.zip 7.4.22.GA-CR1, jboss-eap-incremental-maven-repository.zip 7.4.23
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-feature-server-rhel9, rhoai/odh-mod-arch-automl-rhel9, +8 more Red Hat OpenShift Container Platform 4 openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-monitoring-plugin-rhel9, openshift4/ose-agent-installer-ui-rhel9 Red Hat OpenShift Container Platform 5 openshift5/ose-monitoring-plugin-rhel9, openshift5/ose-agent-installer-ui-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Openshift Data Foundation 4 odf4/mcg-core-rhel9
    affected: workaround, no fix planned “Out of support scope”

8 more affected, 3 more fixed, 3 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/ljharb/qs/security/advisories/GHSA-x5fp-wj9c-mxmx referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
CNA 4.0 6.3 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
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
CNA 4.0 6.3 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
npm qs
>=6.14.2, <6.16.0
6.16.0

Affected products

  • ljharb qs

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of ljharb/qs published their own advisory on GitHub. Reviewed sources take precedence over it.