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Fencer Vulns
medium 6.1

CVE-2026-53666 json

React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration

published 2026-07-23 3 mo ago modified 2026-10-24 16 d ago also EUVD-2026-49628 , GHSA-337j-9hxr-rhxg

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

React Router is a router for React. In versions 6.4.0 through 7.17.0, if application code was written in a way that allows attacker-supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for an attacker to trigger unexpected constructor execution on the client, which would in turn trigger an outbound network request. This is only possible with very specific (and unlikely) application-layer code. Note that this does not impact an application if it is using Declarative Mode. It only impacts Framework Mode and Data Mode applications that perform manual SSR/hydration. This issue has been fixed in version 7.18.0.

Patch / fix

  • npm react-router 7.18.0
  • shopify react-router 7.18.0

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-2026-53666 updated cvss 6.1

react-router: React Router: Information disclosure via client-side constructor execution

  • Red Hat Cryostat 4 react-router 5.3.4, grafana-infinity-datasource-npm 3.7.2_redhat_00002-1, cryostat-openshift-console-plugin-npm 4.2.0_redhat_00003-1
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Exploit Intelligence exploit-intelligence-tech-preview/agent-client-rhel9
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-ui-rhel8, mta/mta-ui-rhel9 Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-ui-rhel8
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Migration Toolkit for Virtualization migration-toolkit-virtualization/mtv-console-plugin-rhel9
    affected: workaround, no fix planned “Out of support scope”
  • 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-pf4-rhel9, network-observability/network-observability-console-plugin-pf5-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Node HealthCheck Operator 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
    affected: workaround, no fix available “Fix deferred”
  • 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
    affected: workaround, no fix available, no fix planned “Out of support scope”
show 10 more
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9
    affected: workaround, no fix planned “Out of support scope”
  • 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 react-router 5.3.4 Red Hat Ansible Automation Platform 2 automation-hub 4.9.8-1.el9ap, python-galaxy-ng 4.9.5-1.el9ap, python3x-galaxy-ng 4.9.5-1.el8ap, python3.11-galaxy-ng 4.9.5-2.el9ap, python3.12-galaxy-ng 4.9.8-1.el9ap, automation-controller 4.5.34-1.el9ap, +6 more Red Hat build of Apache Camel - HawtIO 4 react-router 5.3.4 Red Hat build of Apache Camel for Spring Boot 4 react-router 5.3.4 Red Hat build of Apicurio Registry 3 apicurio/apicurio-registry-ui-rhel8, apicurio/apicurio-registry-ui-rhel9 Red Hat Build of Keycloak react-router 5.3.4
    +1 more products
    Red Hat Build of Podman Desktop rh-podman-desktop.git 1.1.0
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Ceph Storage 9 rhceph/alloy-rhel10 Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Data Grid 8 react-router 5.3.4
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 Red Hat Edge Manager 1 rhem/flightctl-ui-rhel9, rhem/flightctl-ui-rhel10, rhem/flightctl-ui-ocp-rhel9, rhem/flightctl-ui-ocp-rhel10 Red Hat Enterprise Linux 8 cockpit-composer Red Hat Enterprise Linux 9 grafana, ipa-client, ipa-common, ipa-server, ipa-selinux, ipa-client-epn, +17 more Red Hat Enterprise Linux 10 grafana, ipa 4.13.1-4.el10, cockpit-image-builder, opentelemetry-collector Red Hat JBoss Enterprise Application Platform 8 react-router 5.3.4
    +4 more products
    Red Hat JBoss Enterprise Application Platform Expansion Pack react-router 5.3.4 Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +3 more Red Hat OpenShift Container Platform 4 openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-monitoring-plugin-rhel8, openshift4/ose-monitoring-plugin-rhel9, openshift4/ose-agent-installer-ui-rhel9 Red Hat OpenShift Container Platform 5 openshift5/ose-console-rhel9, 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/odf-console-rhel9, odf4/ocs-client-console-rhel9, odf4/odf-multicluster-console-rhel9
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift Dev Spaces devspaces/openvsx-rhel9, devspaces/dashboard-rhel9 Red Hat OpenShift distributed tracing 3 rhosdt/tempo-jaeger-query-rhel9 Red Hat OpenShift GitOps openshift-gitops-1/argocd-rhel8, openshift-gitops-1/argocd-rhel9, openshift-gitops-1/console-plugin-rhel8, openshift-gitops-1/console-plugin-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift Virtualization 4 container-native-virtualization/kubevirt-console-plugin, container-native-virtualization/kubevirt-console-plugin-rhel9
    affected: workaround, no fix planned “Out of support scope”

7 more affected, 5 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
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm react-router
>=6.4.0, <7.18.0
7.18.0

Affected products

  • remix-run react-router

Classification

Weakness
  • CWE-470 Use of Externally-Controlled Input to Select Classes or Code

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.

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