diff --git a/lib/web/fetch/body.js b/lib/web/fetch/body.js
index 0f4ef04d2fe..5b14d22d27a 100644
--- a/lib/web/fetch/body.js
+++ b/lib/web/fetch/body.js
@@ -392,7 +392,7 @@ function bodyMixinMethods (instance) {
       // with this and the following step given a byte sequence bytes: return the
       // result of creating a Uint8Array from bytes in this’s relevant realm.
       return consumeBody(this, (bytes) => {
-        return new Uint8Array(bytes)
+        return new Uint8Array(bytes.buffer, 0, bytes.byteLength)
       }, instance, true)
     }
   }