diff --git a/playground/optimize-deps/cjs-dynamic.js b/playground/optimize-deps/cjs-dynamic.js
index 616dffae4d6c0c..69c11051692272 100644
--- a/playground/optimize-deps/cjs-dynamic.js
+++ b/playground/optimize-deps/cjs-dynamic.js
@@ -22,7 +22,11 @@
   }
 
   const cjsFromCJS = await import('@vitejs/test-dep-cjs-compiled-from-cjs')
-  if (typeof cjsFromCJS.default === 'function') {
+  if (
+    typeof cjsFromCJS.default === 'function' &&
+    typeof cjsFromCJS !== 'function' &&
+    cjsFromCJS.bar === 'bar'
+  ) {
     text('.cjs-dynamic-dep-cjs-compiled-from-cjs', 'ok')
   }
 
diff --git a/playground/optimize-deps/cjs.js b/playground/optimize-deps/cjs.js
index f0201008647889..cd26c373a4765a 100644
--- a/playground/optimize-deps/cjs.js
+++ b/playground/optimize-deps/cjs.js
@@ -7,6 +7,7 @@ import { Socket } from 'phoenix'
 import clip from 'clipboard'
 import cjsFromESM from '@vitejs/test-dep-cjs-compiled-from-esm'
 import cjsFromCJS from '@vitejs/test-dep-cjs-compiled-from-cjs'
+import * as cjsFromCJSNamespace from '@vitejs/test-dep-cjs-compiled-from-cjs'
 
 // Test exporting a name that was already imported
 export { useState } from 'react'
@@ -25,7 +26,11 @@ if (typeof cjsFromESM === 'function') {
   text('.cjs-dep-cjs-compiled-from-esm', 'ok')
 }
 
-if (typeof cjsFromCJS === 'function') {
+if (
+  typeof cjsFromCJS === 'function' &&
+  typeof cjsFromCJSNamespace !== 'function' &&
+  cjsFromCJSNamespace.bar === 'bar'
+) {
   text('.cjs-dep-cjs-compiled-from-cjs', 'ok')
 }
 
diff --git a/playground/optimize-deps/dep-cjs-compiled-from-cjs/index.js b/playground/optimize-deps/dep-cjs-compiled-from-cjs/index.js
index 38d4c85c7c33ce..bb78ebd1f162bd 100644
--- a/playground/optimize-deps/dep-cjs-compiled-from-cjs/index.js
+++ b/playground/optimize-deps/dep-cjs-compiled-from-cjs/index.js
@@ -2,4 +2,5 @@
 function foo() {
   return 'foo'
 }
+foo.bar = 'bar'
 module.exports = foo