diff --git a/lib/buffer.js b/lib/buffer.js
index f86deb03d827b1..96d303d3b2f588 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -132,11 +132,13 @@ addBufferPrototypeMethods(Buffer.prototype);
 
 const constants = ObjectDefineProperties({}, {
   MAX_LENGTH: {
+    __proto__: null,
     value: kMaxLength,
     writable: false,
     enumerable: true
   },
   MAX_STRING_LENGTH: {
+    __proto__: null,
     value: kStringMaxLength,
     writable: false,
     enumerable: true
diff --git a/lib/internal/webstreams/readablestream.js b/lib/internal/webstreams/readablestream.js
index b44df2ff77896d..0e7d33e9b71eb3 100644
--- a/lib/internal/webstreams/readablestream.js
+++ b/lib/internal/webstreams/readablestream.js
@@ -1181,9 +1181,9 @@ function createTeeReadableStream(start, pull, cancel) {
       setupReadableStreamDefaultControllerFromSource(
         this,
         ObjectCreate(null, {
-          start: { value: start },
-          pull: { value: pull },
-          cancel: { value: cancel }
+          start: { __proto__: null, value: start },
+          pull: { __proto__: null, value: pull },
+          cancel: { __proto__: null, value: cancel }
         }),
         1,
         () => 1);
diff --git a/lib/internal/webstreams/util.js b/lib/internal/webstreams/util.js
index 305064ba05a490..524093dc74df66 100644
--- a/lib/internal/webstreams/util.js
+++ b/lib/internal/webstreams/util.js
@@ -49,11 +49,13 @@ const kType = Symbol('kType');
 
 const AsyncIterator = ObjectCreate(AsyncIteratorPrototype, {
   next: {
+    __proto__: null,
     configurable: true,
     enumerable: true,
     writable: true,
   },
   return: {
+    __proto__: null,
     configurable: true,
     enumerable: true,
     writable: true,