diff --git a/packages/next/build/polyfills/object-assign.cjs.js b/packages/next/build/polyfills/object-assign.cjs.js
deleted file mode 100644
index 97fcde1c0d27f..0000000000000
--- a/packages/next/build/polyfills/object-assign.cjs.js
+++ /dev/null
@@ -1 +0,0 @@
-module.exports = Object.assign
diff --git a/packages/next/build/polyfills/object-assign.js b/packages/next/build/polyfills/object-assign.js
index 8cfbca32c571e..97fcde1c0d27f 100644
--- a/packages/next/build/polyfills/object-assign.js
+++ b/packages/next/build/polyfills/object-assign.js
@@ -1 +1 @@
-export default Object.assign
+module.exports = Object.assign
diff --git a/packages/next/build/webpack-config.ts b/packages/next/build/webpack-config.ts
index 200f92d785f8d..5b04fdcae0dec 100644
--- a/packages/next/build/webpack-config.ts
+++ b/packages/next/build/webpack-config.ts
@@ -174,7 +174,7 @@ export default async function getBaseWebpackConfig(
             'object-assign': path.join(
               __dirname,
               'polyfills',
-              'object-assign.cjs.js'
+              'object-assign.js'
             ),
             '@babel/runtime-corejs2/core-js/object/assign':
               'next/dist/build/polyfills/object-assign.js',