diff --git a/package-lock.json b/package-lock.json
index 6a5471d4..2f08e41a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -15503,9 +15503,9 @@
       "dev": true
     },
     "uglify-js": {
-      "version": "3.3.27",
-      "resolved": "https://registry.npmjs.org/uglify-js/-/uglify-js-3.3.27.tgz",
-      "integrity": "sha512-O94wxMSb3td/TlofkITYvYIlvIVdldvNXDVRekzK13CQZuL37ua4nrdXX0Ro7MapfUVzglRHs0/+imPRUdOghg==",
+      "version": "3.4.0",
+      "resolved": "https://registry.npmjs.org/uglify-js/-/uglify-js-3.4.0.tgz",
+      "integrity": "sha512-Jcf5naPkX3rVPSQpRn9Vm6Rr572I1gTtR9LnqKgXjmOgfYQ/QS0V2WRStFR53Bdj520M66aCZqt9uzYXgtGrJQ==",
       "dev": true,
       "requires": {
         "commander": "~2.15.0",
diff --git a/package.json b/package.json
index c867d644..8a020cd7 100644
--- a/package.json
+++ b/package.json
@@ -68,7 +68,7 @@
     "pretty-bytes-cli": "2.0.0",
     "semver": "5.5.0",
     "sinon": "4.5.0",
-    "uglify-js": "3.3.27",
+    "uglify-js": "3.4.0",
     "webpack": "3.12.0",
     "webpack-dev-server": "2.11.2"
   },