React Router's same-origin redirect with path starting // causes open redirect via protocol-relative URL reinterpretation

Open Source Vulnerabilities CVE-2026-40181

React Router is a router for React. In versions 7.0.0 through 7.14.0 and 6.7.0 through 6.30.3, certain URLs passed to the redirect function can trigger an open redirect to an external domain due to path values starting with // being reinterpreted as protocol-relative URLs. The level of impact depends on the validation done by the application prior to returning the redirect. This does not impact applications using Declarative Mode (<BrowserRouter>). This is patched in versions 7.14.1 and 6.30.4.

Open Source Vulnerabilities GHSA-2j2x-hqr9-3h42

Certain URLs passed to the `redirect` function can trigger an open redirect to an external domain depending on the level of validation done by the application prior to returning the `redirect`. > [!NOTE] > This does not impact your React Router application if you are using [Declarative Mode](https://reactrouter.com/start/modes#declarative) (`<BrowserRouter>`)