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Fencer Vulns
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 2026-08-29 2 mo ago modified 2026-09-10 1 mo ago also GHSA-x5fp-wj9c-mxmx , EUVD-2026-68141

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

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
2 mo ago

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

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
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
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

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 Vulns 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.