Medium · published September 27, 2026
Cloudreve before 4.17.0 registers the administrative node test endpoints (POST /api/v4/admin/node/test and POST /api/v4/admin/node/test/downloader) without requiring the Admin.Write OAuth scope, unlike the node create/update/delete routes. An OAuth client that has been authorized by an administrator with only the Admin.Read scope can therefore submit attacker-controlled node definitions and cause the Cloudreve server to issue outbound requests to arbitrary URLs, enabling blind server-side request forgery, internal service probing, and delivery of signed Cloudreve slave-style requests to attacker-chosen endpoints.