diff --git a/src/task-bundle.js b/src/task-bundle.js
index 8205627..bd1e496 100644
--- a/src/task-bundle.js
+++ b/src/task-bundle.js
@@ -194,7 +194,7 @@ class BundleTask {
 
     static applyCustom(onBundle, wpConfig) {
         const { filename: filenameOrig, library: libraryOrig } = wpConfig.output;
-        onBundle(wpConfig);
+        onBundle(wpConfig, webpack);
         const { filename, library } = wpConfig.output;
 
         // Update the `Var2EsmPlugin` instance if necessary