Answer in brief
CVE-2026-33244 records a Medium severity (CVSS 5.4) vulnerability in React Router has stored XSS via unescaped Location header in prerendered redirect HTML. The current sources do not mark it as known exploited. The current feed maps react-router (npm), react-router (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps react-router (npm), react-router (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| react-routernpm | >=7.5.1,<7.13.2 | 7.13.2 |
| react-routernpm | >=7.5.1 <7.13.2 | 7.13.2 |
Published upstream
Jun 3, 2026
Evidence: source:ghsa:source_dates:source-dates:recordSource modified
Sep 8, 2026
Evidence: source:ghsa:source_dates:source-dates:recordFirst seen by HOL
Sep 8, 2026
When using React Router v7 [Framework Mode](https://reactrouter.com/start/modes#framework) with [Pre-rendering](https://reactrouter.com/how-to/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](https://reactrouter.com/start/modes#declarative) (`<BrowserRouter>`) or [Data Mode](https://reactrouter.com/start/modes#data) (`createBrowserRouter`/`<RouterProvider>`).
Quoted source text, attributed separately from HOL analysis.