GHSA-qh8j-hqjv-7m4x

## Summary

In the Astro Node adapter, a request whose `Host` header contains a malformed port (for example `example.com:65536` or `example.com:8080:8080`) produced an invalid request URL. The fallback intended to recover from an unparseable URL reused the same malformed host, so it failed again and raised an uncaught `TypeError: Invalid URL` while the request was being built, before any route ran.

## Impact

The effect depends on the adapter configuration:

- Default configuration (`standalone`): the request returns `500 Internal Server Error` and the server continues running. - With the opt-in `staticHeaders: true` option: the throw reaches a synchronous HTTP handler that does not catch it, becoming an `uncaughtException` that terminates the process.

This is an availability-only issue. It does not expose data or allow code execution. Triggering it requires sending a hand-crafted `Host` header, and many proxies and CDNs reject malformed hosts before they reach the origin.

## Affected versions

`@astrojs/node` <= 11.1.2.

## Patches

Fixed in `@astrojs/node` 11.1.3. When the incoming host cannot be parsed, the request URL now degrades to a host the server controls, so the request is handled instead of throwing. Hosts carrying more than a single `hostname:port` pair are also rejected during host validation.

## Workarounds

Upgrade to `@astrojs/node` 11.1.3 or later. Deployments that terminate malformed `Host` headers at a reverse proxy or CDN are not reachable through this path.

## Credits

Reported by @Celggar.