diff --git a/packages/vite-node/src/client.ts b/packages/vite-node/src/client.ts
index 998464fc2028..fa4b71eb958f 100644
--- a/packages/vite-node/src/client.ts
+++ b/packages/vite-node/src/client.ts
@@ -273,7 +273,7 @@ export class ViteNodeRunner {
 
         // returns undefined, when accessing named exports, if default is not an object
         // but is still present inside hasOwnKeys, this is Node behaviour for CJS
-        if (exports.default === null || typeof exports.default !== 'object') {
+        if (isPrimitive(exports.default)) {
           defineExport(exports, p, () => undefined)
           return true
         }
diff --git a/test/cjs/src/default-function.cjs b/test/cjs/src/default-function.cjs
new file mode 100644
index 000000000000..db64778ef506
--- /dev/null
+++ b/test/cjs/src/default-function.cjs
@@ -0,0 +1,8 @@
+'use strict'
+
+function format() {
+  return ''
+}
+
+module.exports = format
+module.exports.default = format
diff --git a/test/cjs/src/default-function.d.cts b/test/cjs/src/default-function.d.cts
new file mode 100644
index 000000000000..542d181f0123
--- /dev/null
+++ b/test/cjs/src/default-function.d.cts
@@ -0,0 +1,3 @@
+declare function format(): string
+
+export default format
diff --git a/test/cjs/test/function-default.test.ts b/test/cjs/test/function-default.test.ts
new file mode 100644
index 000000000000..51b4b6b930c0
--- /dev/null
+++ b/test/cjs/test/function-default.test.ts
@@ -0,0 +1,13 @@
+import { describe, expect, it } from 'vitest'
+import format from '../src/default-function.cjs'
+
+describe('correctly puts default on default', () => {
+  it('works on default function', () => {
+    expect(format()).toBe('')
+  })
+
+  it('works on nested default function', () => {
+    // @ts-expect-error types defined only default
+    expect(format.default()).toBe('')
+  })
+})