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Fencer Vulns
high 7.5

CVE-2026-59869 json

js-yaml: YAML merge-key chains can force quadratic CPU consumption

published 2026-07-08 4 mo ago modified 2026-10-25 14 d ago also GHSA-52cp-r559-cp3m , EUVD-2026-42301

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 before 3.15.0 and from 4.0.0 before 4.3.0, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in versions 3.15.0 and 4.3.0.

Patch / fix

  • npm js-yaml 3.15.0, 4.3.0
  • nodeca js-yaml 3.15.0, 4.3.0
  • node-js-yaml Debian 14 4.2.0+~4.0.9-2

debian advisories DEBIAN-CVE-2026-59869

  • receptor ansible automation platform inside 2.5, ansible automation platform developer 2.5, ansible automation platform 2.5 1.6.8-1.el8ap
  • receptor ansible automation platform inside 2.6, ansible automation platform inside 2.5, ansible automation platform developer 2.6 +3 more 1.6.8-1.el9ap
  • python3.12-sqlparse ansible automation platform developer 2.5, ansible automation platform 2.5 0.6.0-1.el8ap
  • python3.12-sqlparse ansible automation platform developer 2.6, ansible automation platform developer 2.5, ansible automation platform 2.6 +1 more 0.6.0-1.el9ap
  • python3.12-gitpython ansible automation platform 2.5 3.1.60-1.el8ap
  • python3.12-gitpython ansible automation platform 2.6, ansible automation platform 2.5 3.1.60-1.el9ap
  • automation-gateway-server ansible automation platform 2.5 2.5.20260923-1.el8ap
  • automation-gateway-server ansible automation platform 2.5 2.5.20260923-1.el9ap

red hat advisories RHSA-2026:71114RHSA-2026:71113RHSA-2026:57590RHSA-2026:40415RHSA-2026:37532RHSA-2026:38304

  • velociraptor openSUSE Tumbleweed 0.76.7.0.git145.b60ef1146-1.1

opensuse advisories openSUSE-SU-2026:12070-1

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-2026-59869 updated cvss 7.5

js-yaml: js-yaml: Denial of Service via crafted YAML documents

  • Red Hat Cryostat 4 grafana-infinity-datasource-npm Red Hat Network Observability Operator network-observability/network-observability-console-plugin-rhel9, network-observability/network-observability-console-plugin-pf5-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-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
    affected: workaround, no fix available
  • Red Hat Ansible Automation Platform 2 automation-controller, ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-27/mcp-server-rhel9, ansible-automation-platform-tech-preview/mcp-server-rhel9
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat build of Apicurio Registry 3 apicurio/apicurio-registry-ui-rhel8, apicurio/apicurio-registry-ui-rhel9 Red Hat Build of Podman Desktop rh-podman-desktop.git
    affected: workaround, no fix available
  • Red Hat Ceph Storage 9 rhceph/alloy-rhel10
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9
    affected: workaround, no fix available
  • Red Hat Directory Server 11 389-ds-base Red Hat Directory Server 12 389-ds-base Red Hat Directory Server 13 389-ds-base Red Hat Enterprise Linux 8 grafana, grafana-loki, grafana-mssql, grafana-mysql, grafana-selinux, grafana-graphite, +8 more Red Hat Enterprise Linux 9 grafana, grafana-selinux Red Hat Enterprise Linux 10 grafana
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rust, rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/disk-image-cuda-rhel9
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat Hardened Images nodejs20 20.20.2-1.hum1 Red Hat JBoss Enterprise Application Platform 7 js-yaml 3.14.2 Red Hat OpenShift Container Platform 4 openshift4/ose-monitoring-plugin-rhel8
    affected: workaround, no fix planned “Will not fix”
show 18 more
  • Red Hat OpenShift Container Platform 5 openshift5/ose-console-rhel9, openshift5/ose-monitoring-plugin-rhel9, openshift5/nmstate-console-plugin-rhel9
    affected: workaround, no fix available
  • Red Hat OpenShift GitOps openshift-gitops-1/argocd-rhel8 Red Hat Single Sign-On 7 js-yaml 3.14.2
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Trusted Artifact Signer rhtas/rhtas-console-ui-rhel9 Red Hat Secrets Management Console for Red Hat OpenShift external-secrets-management/console-plugin-rhel9
    affected: workaround, no fix available
  • Red Hat Cryostat 4 on RHEL 9 cryostat/cryostat-grafana-dashboard-rhel9 4.2.0-14, cryostat/cryostat-openshift-console-plugin-rhel9 4.2.0-14
    fixed: vendor fix RHSA-2026:68333
  • Red Hat multicluster engine for Kubernetes 2.6 multicluster-engine/console-mce-rhel9 1784556108
    fixed: vendor fix RHSA-2026:47949
  • Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/console-mce-rhel9 1785078604
    fixed: vendor fix RHSA-2026:47735
  • Red Hat multicluster engine for Kubernetes 2.9 multicluster-engine/console-mce-rhel9 1787079359
    fixed: vendor fix RHSA-2026:59559
  • Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/console-mce-rhel9 1784312384
    fixed: vendor fix RHSA-2026:46885
  • Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/console-mce-rhel9 1786911977
    fixed: vendor fix RHSA-2026:57194
  • Red Hat multicluster engine for Kubernetes 2.17 multicluster-engine/console-mce-rhel9 1786668856
    fixed: vendor fix RHSA-2026:59593
  • Red Hat Advanced Cluster Management for Kubernetes 2.11 rhacm2/console-rhel9 1787687062
    fixed: vendor fix RHSA-2026:60387
  • Red Hat Advanced Cluster Management for Kubernetes 2.13 rhacm2/console-rhel9 1785078581
    fixed: vendor fix RHSA-2026:47737
  • Red Hat Advanced Cluster Management for Kubernetes 2.14 rhacm2/console-rhel9 1787339248
    fixed: vendor fix RHSA-2026:60388
  • Red Hat Advanced Cluster Management for Kubernetes 2.15 rhacm2/console-rhel9 1784578812
    fixed: vendor fix RHSA-2026:46903
  • Red Hat Advanced Cluster Management for Kubernetes 2.16 rhacm2/console-rhel9 1786908361
    fixed: vendor fix RHSA-2026:57191
  • Red Hat Advanced Cluster Management for Kubernetes 2.17 rhacm2/console-rhel9 1787335105
    fixed: vendor fix RHSA-2026:60386
  • Red Hat Advanced Cluster Security 4.9 advanced-cluster-security/rhacs-main-rhel8 1785413210
    fixed: vendor fix RHSA-2026:48872
  • Red Hat Advanced Cluster Security for Kubernetes 4.11 advanced-cluster-security/rhacs-main-rhel9 1785415868
    fixed: vendor fix RHSA-2026:48891

64 more fixed, 78 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
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m referenced PoC, tagged "exploit" by a source, unverified

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
>=3.0.0, <3.15.0
>=4.0.0, <4.3.0
3.15.0
4.3.0

Affected products

  • nodeca js-yaml

Classification

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

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.