diff --git a/package.json b/package.json
index de54746..d664517 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
         "typescript-2.9": "npm:typescript@2.9.x",
         "typescript-3.0": "npm:typescript@3.0.x",
         "typescript-3.1": "npm:typescript@3.1.x",
-        "webpack-merge": "~4.1.4"
+        "webpack-merge": "~4.2.1"
     },
     "devDependencies": {
         "@types/bluebird": "~3.5.24",
diff --git a/yarn.lock b/yarn.lock
index febc054..d0e4f34 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1638,9 +1638,10 @@ validate-npm-package-license@^3.0.1:
     spdx-correct "^3.0.0"
     spdx-expression-parse "^3.0.0"
 
-webpack-merge@~4.1.4:
-  version "4.1.4"
-  resolved "https://registry.yarnpkg.com/webpack-merge/-/webpack-merge-4.1.4.tgz#0fde38eabf2d5fd85251c24a5a8c48f8a3f4eb7b"
+webpack-merge@~4.2.1:
+  version "4.2.1"
+  resolved "https://registry.yarnpkg.com/webpack-merge/-/webpack-merge-4.2.1.tgz#5e923cf802ea2ace4fd5af1d3247368a633489b4"
+  integrity sha512-4p8WQyS98bUJcCvFMbdGZyZmsKuWjWVnVHnAS3FFg0HDaRVrPbkivx2RYCre8UiemD67RsiFFLfn4JhLAin8Vw==
   dependencies:
     lodash "^4.17.5"