diff --git a/build/lib/extensions.js b/build/lib/extensions.js
index 0db1d1d2d4b..eb73cc9f883 100644
--- a/build/lib/extensions.js
+++ b/build/lib/extensions.js
@@ -133,7 +133,7 @@ function fromLocalWebpack(extensionPath, webpackConfigFileName, disableMangle) {
     const packagedDependencies = [];
     const packageJsonConfig = require(path_1.default.join(extensionPath, 'package.json'));
     if (packageJsonConfig.dependencies) {
-        const webpackRootConfig = require(path_1.default.join(extensionPath, webpackConfigFileName));
+        const webpackRootConfig = require(path_1.default.join(extensionPath, webpackConfigFileName)).default;
         for (const key in webpackRootConfig.externals) {
             if (key in packageJsonConfig.dependencies) {
                 packagedDependencies.push(key);
@@ -171,7 +171,7 @@ function fromLocalWebpack(extensionPath, webpackConfigFileName, disableMangle) {
                     result.emit('error', compilation.warnings.join('\n'));
                 }
             };
-            const exportedConfig = require(webpackConfigPath);
+            const exportedConfig = require(webpackConfigPath).default;
             return (Array.isArray(exportedConfig) ? exportedConfig : [exportedConfig]).map(config => {
                 const webpackConfig = {
                     ...config,
diff --git a/build/lib/extensions.ts b/build/lib/extensions.ts
index 80eaec1b8b9..50255d874d8 100644
--- a/build/lib/extensions.ts
+++ b/build/lib/extensions.ts
@@ -99,7 +99,7 @@ function fromLocalWebpack(extensionPath: string, webpackConfigFileName: string,
 	const packagedDependencies: string[] = [];
 	const packageJsonConfig = require(path.join(extensionPath, 'package.json'));
 	if (packageJsonConfig.dependencies) {
-		const webpackRootConfig = require(path.join(extensionPath, webpackConfigFileName));
+		const webpackRootConfig = require(path.join(extensionPath, webpackConfigFileName)).default;
 		for (const key in webpackRootConfig.externals) {
 			if (key in packageJsonConfig.dependencies) {
 				packagedDependencies.push(key);
@@ -145,7 +145,7 @@ function fromLocalWebpack(extensionPath: string, webpackConfigFileName: string,
 				}
 			};
 
-			const exportedConfig = require(webpackConfigPath);
+			const exportedConfig = require(webpackConfigPath).default;
 			return (Array.isArray(exportedConfig) ? exportedConfig : [exportedConfig]).map(config => {
 				const webpackConfig = {
 					...config,