CVE-2026-54299 Astro: Host-header full-read SSRF in core prerendered error-page fetch (prerenderedErrorPageFetch default + unvalidated createRequestFromNodeRequest URL)

Astro is a web framework. Prior to 6.4.6, Astro SSR apps with prerendered error pages /404 or /500 using export const prerender = true fetch those pages over HTTP at runtime when an error occurs. The URL for this fetch is derived from request.url, which in turn gets its origin from the incoming...