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Fencer Vulns
high 8.1

CVE-2026-42211 json

React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE

published 2026-06-02 5 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-33999 , GHSA-49rj-9fvp-4h2h

cvss
8.1
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 7.0.0 through 7.14.1, when using Framework Mode, a combination of steps could potentially allow unauthorized remote code execution (RCE) through external requests. This attack requires the application code to have an existing prototype pollution vulnerability, which can then be leveraged in a 2-step attack where the second step triggers unauthorized RCE on the remote server. This does not impact applications using Declarative Mode (`<BrowserRouter>`) or Data Mode (`createBrowserRouter/<RouterProvider>`). This is patched in version 7.14.2.

Patch / fix

  • npm react-router 7.14.2
  • shopify react-router 7.14.2
  • opentelemetry-collector-contrib hummingbird 1 0.155.0-0.1.hum1

red hat advisories RHSA-2026:29770

  • golang-github-prometheus-prometheus SLE Module for Package Hub 15 SP7 3.13.2-150100.4.40.2
  • grafana Multi Linux Manager Tools SLE-15 12.4.10-150002.4.27.1
  • mgr-push Multi Linux Manager Tools SLE-15 5.2.5-150002.3.12.1
  • spacecmd Multi Linux Manager Tools SLE-15 5.2.10-150002.3.15.1
  • uyuni-tools Multi Linux Manager Tools SLE-Micro-5, Multi Linux Manager Tools SLE-15 5.2.17-150002.3.20.1
  • venv-salt-minion Multi Linux Manager Tools SLE-Micro-5, Multi Linux Manager Tools SLE-15 3006.0-150002.5.22.1
  • spacewalk-client-tools Multi Linux Manager Tools SLE-15 5.2.7-150002.3.12.1
  • golang-github-prometheus-prometheus Multi Linux Manager Tools SLE-15 3.13.2-150002.3.19.1

suse advisories SUSE-SU-2026:4606-1SUSE-SU-2026:4585-1

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-2026-42211 updated cvss 8.1

react-router: React Router: Remote Code Execution via prototype pollution in Framework Mode

  • Red Hat OpenShift Pipelines openshift-pipelines/pipelines-console-plugin-rhel9
    affected: workaround, no fix available
  • Red Hat Ansible Automation Platform 2 automation-hub, python-galaxy-ng, python3x-galaxy-ng, python3.11-galaxy-ng, automation-controller, ansible-on-clouds/aoc-azure-aap-installer-rhel9
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat build of Apache Camel - HawtIO 4 react-router Red Hat build of Apicurio Registry 2 react-router Red Hat build of Apicurio Registry 3 apicurio/apicurio-registry-ui-rhel8, apicurio/apicurio-registry-ui-rhel9 Red Hat Enterprise Linux 10 ipa
    affected: workaround, no fix available
  • Red Hat Process Automation 7 react-router
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Single Sign-On 7 react-router
    affected: workaround, no fix planned “Will not fix”
  • Red Hat build of Keycloak 26.6 rhbk/keycloak-rhel9 26.6-20, rhbk/keycloak-rhel9-operator 26.6-20, rhbk/keycloak-operator-bundle 26.6.7-3
    fixed: vendor fix RHSA-2026:68277
  • Red Hat build of Keycloak 26.6.7
    fixed: vendor fix RHSA-2026:68278
  • Red Hat Data Grid 8.6.2
    fixed: vendor fix RHSA-2026:41951
show 9 more
  • Red Hat Hardened Images opentelemetry-collector-contrib 0.155.0-0.1.hum1
    fixed: vendor fix RHSA-2026:29770
  • Red Hat OpenShift AI 3.4 rhoai/odh-dashboard-rhel9 1787347991, rhoai/odh-mod-arch-maas-rhel9 1787251250, rhoai/odh-mod-arch-gen-ai-rhel9 1786611759, rhoai/odh-mod-arch-mlflow-rhel9 1786612219, rhoai/odh-mod-arch-eval-hub-rhel9 1791861214, rhoai/odh-mod-arch-model-registry-rhel9 1787250617
    fixed: vendor fix RHSA-2026:60520
  • Red Hat Trusted Artifact Signer 1.3 rhtas/rhtas-console-ui-rhel9 1784105894
    fixed: vendor fix RHSA-2026:42085
  • Red Hat Cryostat 4 react-router, grafana-infinity-datasource-npm, cryostat-openshift-console-plugin-npm
    not affected: component not present
  • Red Hat Exploit Intelligence exploit-intelligence-tech-preview/agent-client-rhel9 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 Red Hat Migration Toolkit for Virtualization mtv-candidate/mtv-console-plugin-rhel9, migration-toolkit-virtualization/mtv-console-plugin-rhel9 Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9
    +2 more products
    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, network-observability/network-observability-console-plugin-compat-rhel9 Red Hat Node HealthCheck Operator workload-availability/node-healthcheck-rhel9-operator, workload-availability/node-healthcheck-operator-bundle, workload-availability/node-healthcheck-must-gather-rhel9
    not affected: vulnerable code not present
  • 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
    not affected: vulnerable code not in execute path
  • 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-pf5-rhel9 Red Hat OpenShift Service Mesh 2 openshift-service-mesh/kiali-rhel8, openshift-service-mesh/kiali-ossmc-rhel8 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 Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-main-rhel9 Red Hat AMQ Broker 7 react-router
    not affected: vulnerable code not present
  • Red Hat Ansible Automation Platform 2 automation-gateway, python3.12-galaxy-ng, automation-platform-ui, automation-eda-controller, ansible-automation-platform-26/gateway-rhel9, ansible-automation-platform-27/gateway-rhel9 Red Hat build of Apache Camel for Spring Boot 4 react-router
    not affected: component not present
  • Red Hat Build of Podman Desktop rh-podman-desktop.git Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8 Red Hat Ceph Storage 9 rhceph/alloy-rhel10 Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9 Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Discovery 2 discovery/discovery-ui-rhel9
    +2 more products
    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 pcs, pcs-snmp, dotnet5.0-build-reference-packages
    not affected: vulnerable code not present

20 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
total
Assessed
5 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 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm react-router
>=7.0.0, <7.14.2
7.14.2

Affected products

  • remix-run react-router

Classification

Weakness
  • CWE-502 Deserialization of Untrusted Data

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.