Mealie before 3.21.0 fails to validate user ownership in the ratings and favorites endpoints, allowing authenticated attackers to read any user's recipe ratings and favorites by specifying arbitrary user IDs in the URL path. Attackers can access private recipe identifiers, rating values, and favorite flags belonging to other users across different groups or households.

Mealie's AsyncSafeTransport SSRF guard (mealie/pkgs/safehttp/transport.py) resolves a target hostname once, checks the resolved IP against private-range rules, but then issues the actual outbound HTTP request using the original hostname, which the underlying async transport re-resolves independently. Because the validated IP is never pinned to the actual connection, a DNS-rebinding attacker (returning a public IP to the validation lookup and a private/metadata IP to the real connection) defeats the guard. This is reachable by any authenticated user via /api/recipes/create/url, /api/recipes/test-scrape-url, and /api/recipes/{slug}/image, and the scraper reflects fetched content back to the requester, allowing an authenticated user to read internal HTTP services and cloud-metadata endpoints.