diff --git a/forms/UploadField.php b/forms/UploadField.php
index 41485b489..57926dc77 100644
--- a/forms/UploadField.php
+++ b/forms/UploadField.php
@@ -1432,6 +1432,10 @@ class UploadField_ItemHandler extends RequestHandler {
 	 */
 	public function EditForm() {
 		$file = $this->getItem();
+		if(!$file) return $this->httpError(404);
+		if($file instanceof Folder) return $this->httpError(403);
+		if(!$file->canEdit()) return $this->httpError(403);
+		
 		// Get form components
 		$fields = $this->parent->getFileEditFields($file);
 		$actions = $this->parent->getFileEditActions($file);