CVE-2026-33769: Astro: Remote allowlist bypass via unanchored matchPathname wildcard

This issue concerns Astro’s remotePatterns path enforcement for remote URLs used by server-side fetchers such as the image optimization endpoint. The path matching logic for /* wildcards is unanchored, so a pathname that contains the allowed prefix later in the path can still match. As a result, an attacker can fetch paths outside the intended allowlisted prefix on an otherwise allowed host. In our PoC, both the allowed path and a bypass path returned 200 with the same SVG payload, confirming the bypass.