React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
Priority LOW 28CWE-470Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Partial Red Hat: 47 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0042 36th percentileScored 2026-11-07
Fix Partial react-router (remix-run): 7.18.0react-router (npm): 7.18.0Red Hat: 47 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| remix-run | react-router | 6.4.0 to before 7.18.0 | 7.18.0 | Patch available | CNA |
| — | react-router (npm) | 6.4.0 to before 7.18.0 | 7.18.0 | Patch available | GHSA-337j-9hxr-rhxg |
- react-router Vendorremix-run Affected 6.4.0 to before 7.18.0 Fixed in 7.18.0 Patch available CNA
- react-router (npm) Vendor— Affected 6.4.0 to before 7.18.0 Fixed in 7.18.0 Patch available GHSA-337j-9hxr-rhxg
Remediation
- Fix · CNA react-router (remix-run) Fixed in 7.18.0
- Fix · GHSA-337j-9hxr-rhxg react-router (npm) Fixed in 7.18.0 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Cryostat 4 | Affected | No fix yet: Fix deferred |
| Exploit Intelligence | Affected | No fix planned: Out of support scope |
| Gatekeeper 3 | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Applications 8 | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Containers | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Virtualization | Affected | No fix planned: Out of support scope |
| Multicluster Engine for Kubernetes | Affected | No fix yet: Fix deferred |
| Network Observability Operator | Affected | No fix yet: Fix deferred |
| Node HealthCheck Operator | Affected | No fix planned: Out of support scope |
| OpenShift Lightspeed | Affected | No fix yet: Fix deferred |
| OpenShift Pipelines | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 3 | Affected | No fix yet: Fix deferred |
| Red Hat AMQ Broker 7 | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Management for Kubernetes 2 | Affected | No fix planned: Out of support scope |
| Red Hat Advanced Cluster Security 4 | Affected | No fix yet: Fix deferred |
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat Build of Keycloak | Affected | No fix yet: Fix deferred |
| Red Hat Build of Podman Desktop | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 5 | Affected | No fix planned: Out of support scope |
| Red Hat Ceph Storage 9 | Affected | No fix yet: Fix deferred |
| Red Hat Connectivity Link 1 | Affected | No fix yet: Fix deferred |
| Red Hat Data Grid 8 | Affected | No fix planned: Out of support scope |
| Red Hat Discovery 2 | Affected | No fix yet: Fix deferred |
| Red Hat Edge Manager 1 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat JBoss Enterprise Application Platform 8 | Affected | No fix yet: Fix deferred |
| Red Hat JBoss Enterprise Application Platform Expansion Pack | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift GitOps | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Virtualization 4 | Affected | No fix planned: Out of support scope |
| Red Hat OpenShift distributed tracing 3 | Affected | No fix yet: Fix deferred |
| Red Hat Openshift Data Foundation 4 | Affected | No fix planned: Out of support scope |
| Red Hat Quay 3 | Affected | No fix yet: Fix deferred |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
| Red Hat Single Sign-On 7 | Affected | No fix planned: Out of support scope |
| Red Hat Trusted Artifact Signer | Affected | No fix planned: Out of support scope |
| Red Hat Trusted Profile Analyzer | Affected | No fix yet: Fix deferred |
| Red Hat build of Apache Camel - HawtIO 4 | Affected | No fix yet: Fix deferred |
| Red Hat build of Apache Camel for Spring Boot 4 | Affected | No fix yet: Fix deferred |
| Red Hat build of Apicurio Registry 3 | Affected | No fix yet: Fix deferred |
| Secrets Management Console for Red Hat OpenShift | Affected | No fix planned: Out of support scope |
| Self-service automation portal 2 | Affected | No fix yet: Fix deferred |
Not affected: 5 products
- Red Hat Developer Hub 1
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Hardened Images
Timeline
- 2026-10-02 Threatist record created from CVE-2026-53666
- 2026-10-03 Alias added: GHSA-337j-9hxr-rhxg
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
References
Patch 2
More remix-run React-router vulnerabilities
- TI-2026-40200 React Router: Unauthenticated Denial of Service via Inefficient Route Matching CVSS 4.0HIGH 8.7
- TI-2026-30645 React Router vulnerable to DoS via unbounded path expansion in __manifest endpoint CVSS 3.1HIGH 7.5
- TI-2026-26400 React Router vulnerable to Denial of Service via reflected user input in single-fetch CVSS 3.1HIGH 7.5
- TI-2026-17723 React Router vulnerable to XSS via Open Redirects CVSS 3.1HIGH 8.0
- TI-2026-17585 React Router SSR XSS in ScrollRestoration CVSS 3.1HIGH 8.2
- TI-2026-30532 Deserialization of untrusted data in remix-run react-router CVSS 3.1HIGH 8.1
Sources
- CVE-2026-53666 · CVE Program
- CVE-2026-53666 · NVD
- FIRST EPSS
- GHSA-337j-9hxr-rhxg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-53666 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences