diff --git a/modules/json/filterx-cache-json-file.c b/modules/json/filterx-cache-json-file.c
index 2a69d566c..540e3ff75 100644
--- a/modules/json/filterx-cache-json-file.c
+++ b/modules/json/filterx-cache-json-file.c
@@ -91,7 +91,7 @@ _load_json_file(const gchar *filepath, GError **error)
     {
       g_set_error(error, CACHE_JSON_FILE_ERROR, CACHE_JSON_FILE_ERROR_FILE_OPEN_ERROR,
                   "failed to open file: %s (%s)", filepath, g_strerror(errno));
-      return FALSE;
+      return NULL;
     }
 
   struct json_tokener *tokener = json_tokener_new();
@@ -106,6 +106,9 @@ _load_json_file(const gchar *filepath, GError **error)
           if (ferror(file))
             g_set_error(error, CACHE_JSON_FILE_ERROR, CACHE_JSON_FILE_ERROR_FILE_READ_ERROR,
                         "failed to read file: %s (%s)", filepath, g_strerror(errno));
+          else
+            g_set_error(error, CACHE_JSON_FILE_ERROR, CACHE_JSON_FILE_ERROR_FILE_READ_ERROR,
+                        "failed to read file: %s (unexpected EOF)", filepath);
           break;
         }
 
@@ -123,11 +126,23 @@ _load_json_file(const gchar *filepath, GError **error)
     }
 
   FilterXObject *result = NULL;
-  if (object && (result = filterx_json_new_from_object(object)))
-    filterx_object_make_readonly(result);
-  else
-    json_object_put(object);
 
+  if (!object)
+    goto exit;
+
+  if (json_object_get_type(object) != json_type_object && json_object_get_type(object) != json_type_array)
+    {
+      g_set_error(error, CACHE_JSON_FILE_ERROR, CACHE_JSON_FILE_ERROR_JSON_PARSE_ERROR,
+                  "JSON file must contain an object or an array");
+      json_object_put(object);
+      goto exit;
+    }
+
+  result = filterx_json_new_from_object(object);
+  g_assert(result);
+  filterx_object_make_readonly(result);
+
+exit:
   json_tokener_free(tokener);
   fclose(file);
   return result;