Fixed

This is a security feature that prevents the configuration of CNAME DNS records that point a domain or subdomain to a resource owned by a different Cloudflare user account. It is designed for administrators and website owners who use Cloudflare's DNS and proxy services to protect their domains from hijacking or misconfiguration risks.

• Cross-Account CNAME Blocking: Automatically rejects DNS configurations where a CNAME record points to a hostname controlled by another Cloudflare account, stopping potential security issues before they occur.
• Prevents Domain Takeover: Mitigates a common attack vector where an attacker could claim a subdomain by pointing it to a service they control if the target resource is deleted or misconfigured.
• Enforces Account Boundaries: Maintains clear ownership and security isolation between different customers' resources on the platform.
• Clear Error Messaging: When a violation is detected, visitors see a specific error page (Error 1014) explaining the CNAME cross-user ban, aiding in troubleshooting.
• Guides Secure Configuration: For services like R2 object storage, it directs users to set up custom domains through the proper interface instead of manual CNAME records, ensuring a secure link.