diff --git a/appengine/static-files/package.json b/appengine/static-files/package.json
index f9c2f695e7..d3a5e27424 100644
--- a/appengine/static-files/package.json
+++ b/appengine/static-files/package.json
@@ -21,7 +21,7 @@
     }
   },
   "dependencies": {
-    "express": "4.15.4",
+    "express": "4.21.0",
     "pug": "2.0.0-rc.3"
   },
   "devDependencies": {