CVE-2026-54061: Dgraph Alpha group stores can be replaced via unauthenticated external snapshot import

Dgraph Alpha exposes the RPCs used for external snapshot import on the public gRPC port :9080 without authentication or authorization. As a result, an unauthenticated network client can open StreamExtSnapshot and send Badger stream data to the target group’s store. In addition, the receiver calls Prepare() before processing the stream. This operation deletes and replaces the existing DB data.