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Fencer Intel
high 7.5

CVE-2026-84375 json

js-yaml: maxTotalMergeKeys does not limit CPU use for empty merge sources

published 2mo ago modified last mo. also EUVD-2026-69712 , GHSA-2883-xcg3-v3hh

cvss
7.5
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

js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2, 4.3.2, and 5.4.1, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key <<. An attacker can alias a large sequence of empty mappings into many merge targets, causing O(N * K) processing while totalMergeKeys remains unchanged and the configured resource limit is never reached. A relatively small YAML document can therefore cause prolonged CPU consumption in applications that parse untrusted YAML, and merge processing is enabled by default on these release lines. In v3 & v4, merge is enabled by default so the severity score is higher. This issue is fixed in versions 3.15.2, 4.3.2, and 5.4.1.

Patch / fix

  • npm js-yaml 3.15.2, 4.3.2
  • nodeca js-yaml 3.15.2, 4.3.2, 5.4.1
  • node-js-yaml Debian 14 4.3.2+~4.0.9-1

debian advisories DEBIAN-CVE-2026-84375

  • receptor ansible automation platform 2.6 1.6.8-1.el10ap
  • receptor ansible automation platform inside 2.6, ansible automation platform developer 2.6, ansible automation platform 2.6 1.6.8-1.el9ap
  • python-sqlparse ansible automation platform developer 2.6, ansible automation platform 2.6 0.6.0-1.el10ap
  • python3-sqlparse ansible automation platform developer 2.6, ansible automation platform 2.6 0.6.0-1.el10ap
  • python3.12-sqlparse ansible automation platform developer 2.6, ansible automation platform 2.6 0.6.0-1.el9ap
  • python3.12-gitpython ansible automation platform 2.6 3.1.60-1.el9ap
  • automation-controller ansible automation platform developer 2.6, ansible automation platform 2.6 4.7.17-1.el9ap
  • automation-platform-ui ansible automation platform 2.6 2.6.14-1.el9ap

red hat advisories RHSA-2026:71113RHSA-2026:63165RHSA-2026:63164RHSA-2026:62813RHSA-2026:62810

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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-2026-84375 updated cvss 7.5

js-yaml: js-yaml: Denial of Service vulnerability in YAML parsing

  • Red Hat Ansible Automation Orchestrator 2026 ansible-automation-platform/automation-orchestrator-ui-rhel9 Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9 Red Hat Node HealthCheck Operator workload-availability/node-remediation-console-rhel8, workload-availability/node-remediation-console-rhel9, workload-availability/node-healthcheck-rhel9-operator, workload-availability/node-healthcheck-operator-bundle, workload-availability/node-healthcheck-must-gather-rhel9 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-rhel9, openshift-pipelines/pipelines-console-plugin-pf5-rhel9 Red Hat 3scale API Management Platform 2 3scale-amp2/system-rhel9
    affected: no fix available
  • Red Hat Ansible Automation Platform 2 automation-controller 4.7.16-1.el9ap, ansible-automation-platform-24/lightspeed-rhel8
    affected: no fix planned “Will not fix”
  • Red Hat build of Apache Camel - HawtIO 4 rhbac-4/hawtio-gateway-rhel9 Red Hat build of Apicurio Registry 3 apicurio/apicurio-registry-ui-rhel8, apicurio/apicurio-registry-gitops-sync-rhel9 Red Hat Build of Podman Desktop rh-podman-desktop, rh-podman-desktop.git 1.1.0
    affected: no fix available
  • 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 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 Red Hat Ceph Storage 9 ceph, cephadm, librbd1, librgw2, rbd-nbd, ceph-mib, +20 more
    affected: no fix available “Fix deferred”
  • Red Hat Certification Program for Red Hat Enterprise Linux 9 redhat-certification-cnf 9.0-20240522.1.el9 Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9, rhcl-1/rhcl-rhdh-dynamic-plugin-rhel9
    affected: no fix available
  • Red Hat Directory Server 11 389-ds-base 1.4.3.39-26.module+el8dsrv+24682+4ba9f90e Red Hat Directory Server 12 389-ds-base 2.2.7-17.module+el9dsrv+24586+9fc9d4dc Red Hat Directory Server 13 389-ds-base 3.0.6-2.el10dsrv
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 8 grafana, 389-ds-base, grafana-loki, grafana-mssql, grafana-mysql, cockpit-389-ds, +15 more Red Hat Enterprise Linux 9 npm, nodejs, grafana, 389-ds-base, nodejs-libs, python3-lib389, +7 more Red Hat Enterprise Linux 10 ceph, nodejs26 26.1.0-1.el10, nodejs22 22.23.1-3.el10_0, nodejs24 24.19.0-1.el10_2, grafana 10.2.6-28.el10_2.4, rh-podman-desktop 1.1.2-1.el10_2 Red Hat Enterprise Linux AI (RHEL AI) 3 rust 1.92.0-1.el10, rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/disk-image-cuda-rhel9
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat Fuse 7 js-yaml 3.13.1 Red Hat Hardened Images nodejs25 25.9.0-1.6.hum1, nodejs20 20.20.2-1.2.hum1
    affected: no fix planned “Will not fix”
show 8 more
  • Red Hat JBoss Enterprise Application Platform 8 jboss-eap.1-runtime-maven-repository.zip 8.1.0 Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-operator-rhel9, rhoai/odh-mod-arch-agent-ops-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-monitoring-plugin-rhel8, openshift4/ose-monitoring-plugin-rhel9 Red Hat OpenShift Container Platform 5 openshift5/ose-console-rhel9, openshift5/ose-monitoring-plugin-rhel9, openshift5/nmstate-console-plugin-rhel9 Red Hat Openshift Data Foundation 4 odf4/ocs-client-console-rhel9, odf4/odf-multicluster-console-rhel9
    affected: no fix available
  • Red Hat OpenShift GitOps microshift-gitops 1.19.2-36.el9, openshift-gitops-1/argocd-rhel8, openshift-gitops-argocd-cli 1.19.2-36.el9 Red Hat Single Sign-On 7 js-yaml 3.13.1 Red Hat Secrets Management Console for Red Hat OpenShift external-secrets-management/console-plugin-rhel9
    affected: no fix planned “Will not fix”
  • Red Hat Cluster Observability Operator 1.5 cluster-observability-operator/distributed-tracing-console-plugin-pf4-rhel9 1793661804, cluster-observability-operator/distributed-tracing-console-plugin-pf4-rhel9 1793823428
    fixed: vendor fix RHSA-2026:95591
  • Red Hat Network Observability (NETOBSERV) 1.12.3 network-observability/network-observability-console-plugin-rhel9 1789978277, network-observability/network-observability-console-plugin-pf5-rhel9 1789978780
    fixed: vendor fix RHSA-2026:70593
  • Red Hat Advanced Cluster Management for Kubernetes 2.13 rhacm2/console-rhel9 1792883111
    fixed: vendor fix RHSA-2026:92307
  • Red Hat Advanced Cluster Security for Kubernetes 4.11 advanced-cluster-security/rhacs-main-rhel9 1789411320
    fixed: vendor fix RHSA-2026:67714
  • Red Hat Advanced Cluster Security for Kubernetes for IBM Power, little endian 4.10 advanced-cluster-security/rhacs-main-rhel8 1789411269
    fixed: vendor fix RHSA-2026:67711
  • Red Hat Ansible Automation Platform 2.1 ansible-automation-platform/automation-portal 1790254963
    fixed: vendor fix RHSA-2026:72712

42 more fixed, 54 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
none
Automatable
yes
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).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm js-yaml
>=4.0.0, <4.3.2
>=3.0.0, <3.15.2
4.3.2
3.15.2

Affected products

  • nodeca js-yaml

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-407 Inefficient Algorithmic Complexity

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 nodeca/js-yaml published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.