CVE-2026-28792: TinaCMS CLI Dev Server Vulnerable to Cross-Origin File Exfiltration via CORS Misconfiguration + Path Traversal in TinaCMS

The TinaCMS CLI dev server combines a permissive CORS configuration (Access-Control-Allow-Origin: *) with the path traversal vulnerability (previously reported) to enable a browser-based drive-by attack. A remote attacker can enumerate the filesystem, write arbitrary files, and delete arbitrary files on developer’s machines by simply tricking them into visiting a malicious website while tinacms dev is running.