diff --git a/packages/plugin-legacy/src/index.ts b/packages/plugin-legacy/src/index.ts
index 0c9fb1c8c68d33..1a5e86e46019be 100644
--- a/packages/plugin-legacy/src/index.ts
+++ b/packages/plugin-legacy/src/index.ts
@@ -578,7 +578,8 @@ async function buildPolyfillChunk(
     plugins: [polyfillsPlugin(imports, excludeSystemJS)],
     build: {
       write: false,
-      target: false,
+      // if a value above 'es5' is set, esbuild injects helper functions which uses es2015 features
+      target: 'es5',
       minify,
       assetsDir,
       rollupOptions: {