diff --git a/src/applications/files/controller/PhabricatorFileDocumentController.php b/src/applications/files/controller/PhabricatorFileDocumentController.php
--- a/src/applications/files/controller/PhabricatorFileDocumentController.php
+++ b/src/applications/files/controller/PhabricatorFileDocumentController.php
@@ -7,6 +7,10 @@
   private $engine;
   private $ref;
 
+  public function shouldAllowPublic() {
+    return true;
+  }
+
   public function handleRequest(AphrontRequest $request) {
     $viewer = $request->getViewer();