diff --git a/packages/angular_devkit/build_angular/src/webpack/plugins/common-js-usage-warn-plugin.ts b/packages/angular_devkit/build_angular/src/webpack/plugins/common-js-usage-warn-plugin.ts
index ae0818772799..d9383074aa6a 100644
--- a/packages/angular_devkit/build_angular/src/webpack/plugins/common-js-usage-warn-plugin.ts
+++ b/packages/angular_devkit/build_angular/src/webpack/plugins/common-js-usage-warn-plugin.ts
@@ -15,8 +15,8 @@ import { isWebpackFiveOrHigher } from '../../utils/webpack-version';
 const CommonJsRequireDependency = require('webpack/lib/dependencies/CommonJsRequireDependency');
 const AMDDefineDependency = require('webpack/lib/dependencies/AMDDefineDependency');
 
-// The below is extended because there are not in the typings
-interface WebpackModule extends compilation.Module {
+// The below is used to remain compatible with both Webpack 4 and 5
+interface WebpackModule {
   name?: string;
   rawRequest?: string;
   dependencies: WebpackModule[];
diff --git a/packages/angular_devkit/build_angular/src/webpack/plugins/optimize-css-webpack-plugin.ts b/packages/angular_devkit/build_angular/src/webpack/plugins/optimize-css-webpack-plugin.ts
index e44fc869cebf..649d2b97e034 100644
--- a/packages/angular_devkit/build_angular/src/webpack/plugins/optimize-css-webpack-plugin.ts
+++ b/packages/angular_devkit/build_angular/src/webpack/plugins/optimize-css-webpack-plugin.ts
@@ -36,7 +36,7 @@ function hook(
       });
     } else {
       compilation.hooks.optimizeChunkAssets
-        .tapPromise(PLUGIN_NAME, (chunks: compilation.Chunk[]) => {
+        .tapPromise(PLUGIN_NAME, (chunks: Iterable<compilation.Chunk>) => {
           const files: string[] = [];
           for (const chunk of chunks) {
             if (!chunk.files) {