diff --git a/packages/vite/src/node/http.ts b/packages/vite/src/node/http.ts
index f1266ddb93ba12..c07fd41ba9060d 100644
--- a/packages/vite/src/node/http.ts
+++ b/packages/vite/src/node/http.ts
@@ -126,7 +126,7 @@ export async function resolveHttpsConfig(
 ): Promise<HttpsServerOptions | undefined> {
   if (!https) return undefined
 
-  const httpsOption = isObject(https) ? https : {}
+  const httpsOption = isObject(https) ? { ...https } : {}
 
   const { ca, cert, key, pfx } = httpsOption
   Object.assign(httpsOption, {