CVE-2026-33244: React Router has stored XSS via unescaped Location header in prerendered redirect HTML

June 3, 2026

When using React Router v7 Framework Mode with Pre-rendering enabled, an improper neutralization of the HTTP Location header value can permit Cross-Site Scripting (XSS) in statically generated HTML files if the redirect location comes from an untrusted source.

[!NOTE] This does not impact your React Router application if you are using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>).

References

github.com/advisories/GHSA-f22v-gfqf-p8f3
github.com/remix-run/react-router/security/advisories/GHSA-f22v-gfqf-p8f3
nvd.nist.gov/vuln/detail/CVE-2026-33244

Code Behaviors & Features

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