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Home / Threats / CVE-2026-21884

CVE-2026-21884 - React Router Plugin

CVE-2026-21884

Vulnerability CVE-2026-21884 PLUGIN react-router HIGH

React Router is a router for React. In @remix-run/react version prior to 2.17.3. and react-router 7.0.0 through 7.11.0, a XSS vulnerability exists in in React Router's API in Framework Mode when using the getKey/storageKey props during Server-Side Rendering which could allow arbitrary JavaScript execution during SSR if untrusted content is used to generate the keys. There is no impact if server-side rendering in Framework Mode is disabled, or if Declarative Mode () or Data Mode (createBrowserRouter/) is being used. This issue has been patched in @remix-run/react version 2.17.3 and react-router version 7.12.0.

CVE-2026-21884

HIGH CVSS 8.2 Published 2026-01-10 Updated 2026-01-30
AI Risk Critical (94/100) Active Exploit: Likely Published Exploit: Public exploit references found Priority: P1 Immediate
Severity Band HIGH
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Affected Components 1
Reference Links 1
AI Risk Engine Critical (94/100)
Exploitability High
Active Exploitation Likely
Published Exploit Status Public exploit references found

Threat Timeline

  1. 2026-01-10 CVE published and first recorded in the threat feed.
  2. 2026-01-30 Record updated with latest vulnerability metadata.
  3. 2026-04-09 AI technical context refreshed for mitigation and impact guidance.
  4. Now Monitoring for follow-up changes, linked references, and new related CVEs.

AI Context

Machine-generated threat intelligence

AI Updated 12 days ago

AI enriched 12 days ago (2026-04-09 08:07 UTC)

Technical Summary

React Router is a router for React. In @remix-run/react version prior to 2.17.3. and react-router 7.0.0 through 7.11.0, a XSS vulnerability exists in in React Router's API in Framework Mode when using the getKey/storageKey props during Server-Side Rendering which could allow arbitrary JavaScript execution during SSR if untrusted content is used to generate the keys. There is no impact if server-side rendering in Framework Mode is disabled, or if Declarative Mode () or Data Mode (createBrowserRouter/) is being used. This…

Potential Impact

Severity is HIGH (CVSS 8.2). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as High based on published exploit references.

Primary risk drivers: published exploit references

Mitigation Recommendations

Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.

Detection & Monitoring

Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.

Business Impact Lens

Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

React Router PLUGIN · react-router Affected: >= remix-runreact2.17.3, < 2.17.3 Fixed in: 2.17.3
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