diff --git a/packages/vite/src/node/config.ts b/packages/vite/src/node/config.ts
index 9a60343ad69ccb..f5b4f83e1a6eb1 100644
--- a/packages/vite/src/node/config.ts
+++ b/packages/vite/src/node/config.ts
@@ -1724,6 +1724,8 @@ async function bundleConfigFile(
     format: isESM ? 'esm' : 'cjs',
     mainFields: ['main'],
     sourcemap: 'inline',
+    // the last slash is needed to make the path correct
+    sourceRoot: path.dirname(fileName) + path.sep,
     metafile: true,
     define: {
       __dirname: dirnameVarName,