The Dragonfly scheduler's v1 gRPC service exposes an unauthenticated SSRF via the DownloadTinyFile function. When a peer reports a successful tiny task download, the scheduler issues an HTTP GET request to the IP and port specified in the attacker-controlled PeerHost.Ip and PeerHost.DownPort fields without validating the destination address. The HTTP client uses a bare http.Transport with no address filtering, allowing requests to internal IPs including loopback, link-local, and RFC1918 ranges. The fetched response is stored in Task.DirectPiece and can be served to other peers, enabling data exfiltration of up to 128 bytes per request. The scheduler runs with insecure transport credentials by default and lacks authentication interceptors, allowing remote unauthenticated clients to invoke vulnerable RPC methods. The port is restricted to >=1024 by proto validation, excluding port 80. This vulnerability was verified in version 2.4.4-rc.3.

An unauthenticated remote attacker can exploit this SSRF vulnerability to make the scheduler connect to arbitrary internal network addresses and ports (>=1024). This enables blind reachability probing of internal hosts and limited data exfiltration (up to 128 bytes) from internal HTTP services into the scheduler's Task.DirectPiece field, which can then be served to other peers. There is no remote code execution or write capability. The impact is limited to information disclosure and network reconnaissance within the internal environment accessible to the scheduler.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should avoid deploying the scheduler with default insecure transport credentials and should enable mTLS or other authentication mechanisms to restrict access to the gRPC service. Additionally, network-level controls should restrict access to the scheduler service to trusted clients only. Review and update the scheduler configuration to enable TLS and authentication interceptors to prevent unauthenticated access.