diff --git a/packages/kit/src/install-fetch.js b/packages/kit/src/install-fetch.js
index 629e38884996..aee7971d76c5 100644
--- a/packages/kit/src/install-fetch.js
+++ b/packages/kit/src/install-fetch.js
@@ -5,18 +5,22 @@ export function __fetch_polyfill() {
 	Object.defineProperties(globalThis, {
 		fetch: {
 			enumerable: true,
+			configurable: true,
 			value: fetch
 		},
 		Response: {
 			enumerable: true,
+			configurable: true,
 			value: Response
 		},
 		Request: {
 			enumerable: true,
+			configurable: true,
 			value: Request
 		},
 		Headers: {
 			enumerable: true,
+			configurable: true,
 			value: Headers
 		}
 	});