diff --git a/package.json b/package.json
index 3b07f7504a..6d372a4162 100644
--- a/package.json
+++ b/package.json
@@ -46,8 +46,7 @@
     "regenerator": "0.6.7",
     "chokidar": "0.10.0",
     "source-map-support": "0.2.7",
-    "esutils": "1.1.4",
-    "acorn": "0.9.0",
+    "acorn": "0.9.1",
     "ast-types": "0.5.3"
   },
   "devDependencies": {