Astro: Malformed port in the Host header can crash the Node adapter

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.