The `parseUrl` function in `ServerPlatformLocation` uses `new URL(urlStr, origin)` to parse incoming request URLs during SSR. Per the WHATWG URL specification, protocol-relative URLs (`//evil.com`) and backslash-prefixed URLs (`/\evil.com`) can override the hostname component of the base URL.
This vulnerability typically manifests in SSR setups (e.g., Express) where `req.url` is passed directly to `renderApplication` or `renderModule`:
```typescript
// Example usage in an Express server handling: http://localhost:4000//evil.com
app.get('*', async (req, res) => {
const html = await renderApplication(bootstrap, {
document: template,
url: req.url, // req.url is "//evil.com"
});
res.send(html);
});
```
(cherry picked from commit ede7c58a2a)
The existing implementation of `PlatformLocation` uses a custom URL parsing mechanism that can be brittle and doesn't properly update the `href` property. This change refactors the URL parsing to use the native `URL` constructor, providing more robust and accurate parsing of URLs, which also correctly updates the `href` property.
The tests for `PlatformLocation` have also been moved to a dedicated file to improve organization and clarity.
PR Close#64494
