Shopware: SSRF in Media External-Link Endpoint Bypasses IP Validation

Shopware is an open commerce platform. Prior to 6.6.10.18 and 6.7.10.1, the `/api/_action/media/external-link` endpoint allows authenticated admin users to make server-side HTTP HEAD requests to arbitrary internal IP addresses. While the parallel `uploadFromURL` flow validates target IPs against private/reserved ranges via `FileUrlValidator`, the `linkURL` flow only performs a URL format check (regex for `http://` or `https://` prefix), allowing SSRF to internal network services and cloud metadata endpoints. This issue is fixed in versions 6.6.10.18 and 6.7.10.1.