diff --git a/lib/pleroma/plugs/uploaded_media.ex b/lib/pleroma/plugs/uploaded_media.ex
index 36ff024a7..94147e0c4 100644
--- a/lib/pleroma/plugs/uploaded_media.ex
+++ b/lib/pleroma/plugs/uploaded_media.ex
@@ -41,6 +41,7 @@ defmodule Pleroma.Plugs.UploadedMedia do
         conn ->
           conn
       end
+      |> merge_resp_headers([{"content-security-policy", "sandbox"}])
 
     config = Pleroma.Config.get(Pleroma.Upload)