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Fencer Vulns
high 7.5

CVE-2026-73643 json

js-yaml: Exponential parsing time in the flow collections leads to denial of service

published 2026-07-24 3 mo ago modified 2026-10-24 15 d ago also GHSA-pm4m-ph32-ghv5 , EUVD-2026-58185

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 42%
public exploits
0
none known

Summary

js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 until 5.2.2, parsing a small YAML document can take exponential time when an application calls load() or loadAll() on untrusted input. In src/parser/parser.ts, readFlowCollection uses restoreState and calls parseNode a second time when a flow-sequence entry is recognized as a key: value pair. If the key is a nested flow sequence of the same shape, every level is parsed twice, causing O(2^n) work and allowing an input under 200 bytes to keep one CPU busy for minutes, block the Node.js event loop, and stall the process. No anchors, aliases, merges, tags, or nondefault options are required. This issue is fixed in version 5.2.2.

Patch / fix

  • npm js-yaml 5.2.2

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-2026-73643 updated cvss 7.5

js-yaml: js-yaml: Denial of Service via exponential parsing in flow collections

  • 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
    affected: workaround, no fix available
  • 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, no fix planned “Will not fix”
  • Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-main-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Ceph Storage 4 ocs4/rhceph-rhel8 Red Hat Ceph Storage 9 rhceph/alloy-rhel10
    affected: workaround, no fix planned “Out of support scope”
  • 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, no fix planned “Will not fix”
  • Red Hat OpenShift Container Platform 5 openshift5/nmstate-console-plugin-rhel9 Red Hat Openshift Data Foundation 4 odf4/ocs-client-console-rhel9, odf4/odf-multicluster-console-rhel9
    affected: workaround, no fix available
  • Red Hat OpenShift GitOps openshift-gitops-1/argocd-rhel8, openshift-gitops-1/argocd-rhel9 Red Hat Trusted Artifact Signer rhtas/rhtas-console-ui-rhel9 Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9 Red Hat Secrets Management Console for Red Hat OpenShift external-secrets-management/console-plugin-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Cluster Observability Operator 1.5 cluster-observability-operator/monitoring-console-plugin-pf6-rhel9 1787597578
    fixed: vendor fix RHSA-2026:61314
show 23 more
  • Red Hat Ansible Automation Platform 2.2 ansible-automation-platform/bootc-automation-portal-rhel9 1788943531
    fixed: vendor fix RHSA-2026:66003
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 1788206196
    fixed: vendor fix RHSA-2026:61783
  • Red Hat Edge Manager 1.1 rhem/flightctl-ui-rhel10 1789486181, rhem/flightctl-ui-ocp-rhel9 1789486446, rhem/flightctl-ui-ocp-rhel10 1789486226
    fixed: vendor fix RHSA-2026:68044
  • Red Hat Edge Manager 1.2 rhem/flightctl-ui-rhel9 1789486750, rhem/flightctl-ui-rhel10 1789488111, rhem/flightctl-ui-ocp-rhel9 1789486476, rhem/flightctl-ui-ocp-rhel10 1789485920
    fixed: vendor fix RHSA-2026:68006
  • Red Hat Migration Toolkit 1.8 rhmtc/openshift-migration-ui-rhel8 1789546373
    fixed: vendor fix RHSA-2026:68681
  • Red Hat OpenShift AI 2.25 rhoai/odh-dashboard-rhel9 1788312226, rhoai/odh-mod-arch-model-registry-rhel9 1788312157, rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9 1787801527
    fixed: vendor fix RHSA-2026:65126
  • Red Hat OpenShift AI 3.4 rhoai/odh-dashboard-rhel9 1791861020, rhoai/odh-mod-arch-maas-rhel9 1793001859, rhoai/odh-feature-server-rhel9 1791863220, rhoai/odh-mod-arch-automl-rhel9 1791861032, rhoai/odh-mod-arch-gen-ai-rhel9 1791861479, rhoai/odh-mod-arch-mlflow-rhel9 1793001851, +4 more
    fixed: vendor fix RHSA-2026:84734
  • Red Hat OpenShift Container Platform 4.17 openshift4/nmstate-console-plugin-rhel9 1789937643
    fixed: vendor fix RHSA-2026:70588
  • Red Hat OpenShift Container Platform 4.18 openshift4/nmstate-console-plugin-rhel9 1789904088
    fixed: vendor fix RHSA-2026:70618
  • Red Hat OpenShift Container Platform 4.19 openshift4/nmstate-console-plugin-rhel9 1788312221
    fixed: vendor fix RHSA-2026:63050
  • Red Hat OpenShift Container Platform 4.20 openshift4/nmstate-console-plugin-rhel9 1787837308
    fixed: vendor fix RHSA-2026:60447
  • Red Hat OpenShift Container Platform 4.21 openshift4/nmstate-console-plugin-rhel9 1787590372
    fixed: vendor fix RHSA-2026:60478
  • Red Hat OpenShift Container Platform 4.22 openshift4/nmstate-console-plugin-rhel9 1787744843
    fixed: vendor fix RHSA-2026:60442
  • Red Hat Openshift Data Foundation 4.19 odf4/odf-console-rhel9 1793126829
    fixed: vendor fix RHSA-2026:92650
  • Red Hat Trusted Artifact Signer 1.4 rhtas/rekor-search-ui-rhel9 1791534339
    fixed: vendor fix RHSA-2026:83598
  • Red Hat Cluster Observability Operator 1.5 cluster-observability-operator/perses-rhel9 1787593946, cluster-observability-operator/thanos-rhel9 1787594087, cluster-observability-operator/korrel8r-rhel9 1787593952, cluster-observability-operator/prometheus-rhel9 1787593705, cluster-observability-operator/alertmanager-rhel9 1787593799, cluster-observability-operator/perses-rhel9-operator 1787593697, +18 more
    not affected: vulnerable code not present
  • Red Hat Cryostat 4 cryostat/cryostat-openshift-console-plugin-rhel9
    not affected: component not present
  • Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat Migration Toolkit for Applications 8 mta/mta-ui-rhel9
    not affected: vulnerable code not present
  • Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9 Red Hat Network Observability Operator network-observability/network-observability-console-plugin-rhel9, network-observability/network-observability-console-plugin-pf5-rhel9 Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9, openshift-service-mesh/kiali-ossmc-rhel9, openshift-service-mesh/kiali-rhel9-operator, openshift-service-mesh/kiali-operator-bundle
    not affected: component not present
  • Red Hat 3scale API Management Platform 2 3scale-amp2/system-rhel8
    not affected: vulnerable code not present
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9
    not affected: component not present
  • Red Hat AMQ Broker 7 amq-broker-bin.zip 7.14.1.CR2, amq-broker-maven-repository.zip 7.14.1.CR2 Red Hat Ansible Automation Platform 2 automation-controller 4.6.31-1.el9ap, automation-platform-ui 2.6.12-1.el9ap, automation-gateway 2.5.20260804-1.el9ap, automation-eda-controller 1.0.11-1.el8ap, ansible-automation-platform-26/gateway-rhel9, ansible-automation-platform-27/gateway-rhel9, +5 more
    not affected: vulnerable code not present

49 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
2 mo ago

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nodeca/js-yaml/security/advisories/GHSA-pm4m-ph32-ghv5 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
>=5.0.0, <5.2.2
5.2.2

Affected products

  • nodeca js-yaml

Classification

Weakness
  • CWE-407 Inefficient Algorithmic Complexity

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.