diff --git a/package.json b/package.json
index 8a452d3fa4..61a1654978 100644
--- a/package.json
+++ b/package.json
@@ -50,7 +50,7 @@
     "walk": "2.3.9"
   },
   "devDependencies": {
-    "clean-css": "3.4.19",
+    "clean-css": "3.4.20",
     "coveralls": "2.11.14",
     "debounce": "^1.0.0",
     "eslint": "3.5.0",