Describe CVE-2021-29490.
What is CVE-2021-29490?
Jellyfin is a free software media system that provides media from a dedicated server to end-user devices via multiple apps. Verions prior to 10.7.3 vulnerable to unauthenticated Server-Side Request Forgery (SSRF) attacks via the imageUrl parameter. This issue potentially exposes both internal and external HTTP servers or other resources available via HTTP `GET` that are visible from the Jellyfin server. The vulnerability is patched in version 10.7.3. As a workaround, disable external access to the API endpoints `/Items/*/RemoteImages/Download`, `/Items/RemoteSearch/Image` and `/Images/Remote` via reverse proxy, or limit to known-friendly IPs..