nodejs · nodejs-github-bot · Apr 16, 2026 · Apr 8, 2026 · Apr 8, 2026
diff --git a/lib/internal/crypto/webidl.js b/lib/internal/crypto/webidl.js
@@ -31,6 +31,7 @@ const {
 } = primordials;
 
 const {
+  converters: sharedConverters,
   makeException,
   createEnumConverter,
   createSequenceConverter,
@@ -43,11 +44,10 @@ const {
 } = require('internal/util');
 const { CryptoKey } = require('internal/crypto/webcrypto');
 const {
-  getDataViewOrTypedArrayBuffer,
   validateMaxBufferLength,
   kNamedCurveAliases,
 } = require('internal/crypto/util');
-const { isArrayBuffer, isSharedArrayBuffer } = require('internal/util/types');
+const { isSharedArrayBuffer } = require('internal/util/types');
 
 // https://tc39.es/ecma262/#sec-tonumber
 function toNumber(value, opts = kEmptyObject) {
@@ -193,8 +193,6 @@ converters.object = (V, opts) => {
   return V;
 };
 
-const isNonSharedArrayBuffer = isArrayBuffer;
-
 /**
  * @param {string | object} V - The hash algorithm identifier (string or object).
  * @param {string} label - The dictionary name for the error message.
@@ -223,25 +221,7 @@ converters.Uint8Array = (V, opts = kEmptyObject) => {
   return V;
 };
 
-converters.BufferSource = (V, opts = kEmptyObject) => {
-  if (ArrayBufferIsView(V)) {
-    if (isSharedArrayBuffer(getDataViewOrTypedArrayBuffer(V))) {
-      throw makeException(
-        'is a view on a SharedArrayBuffer, which is not allowed.',
-        opts);
-    }
-
-    return V;
-  }
-
-  if (!isNonSharedArrayBuffer(V)) {
-    throw makeException(
-      'is not instance of ArrayBuffer, Buffer, TypedArray, or DataView.',
-      opts);
-  }
-
-  return V;
-};
+converters.BufferSource = sharedConverters.BufferSource;
 
 converters['sequence<DOMString>'] = createSequenceConverter(
   converters.DOMString);

diff --git a/lib/internal/webidl.js b/lib/internal/webidl.js
@@ -1,8 +1,10 @@
 'use strict';
 
 const {
+  ArrayBufferIsView,
   ArrayPrototypePush,
   ArrayPrototypeToSorted,
+  DataViewPrototypeGetBuffer,
   MathAbs,
   MathMax,
   MathMin,
@@ -19,6 +21,7 @@ const {
   Symbol,
   SymbolIterator,
   TypeError,
+  TypedArrayPrototypeGetBuffer,
 } = primordials;
 
 const {
@@ -28,6 +31,11 @@ const {
   },
 } = require('internal/errors');
 const { kEmptyObject } = require('internal/util');
+const {
+  isArrayBuffer,
+  isDataView,
+  isSharedArrayBuffer,
+} = require('internal/util/types');
 
 const converters = { __proto__: null };
 
@@ -382,6 +390,47 @@ function createInterfaceConverter(name, I) {
   };
 }
 
+function getDataViewOrTypedArrayBuffer(V) {
+  return isDataView(V) ?
+    DataViewPrototypeGetBuffer(V) : TypedArrayPrototypeGetBuffer(V);
+}
+
+// https://webidl.spec.whatwg.org/#ArrayBufferView
+converters.ArrayBufferView = (V, opts = kEmptyObject) => {
+  if (!ArrayBufferIsView(V)) {
+    throw makeException(
+      'is not an ArrayBufferView.',
+      opts);
+  }
+  if (isSharedArrayBuffer(getDataViewOrTypedArrayBuffer(V))) {
+    throw makeException(
+      'is a view on a SharedArrayBuffer, which is not allowed.',
+      opts);
+  }
+
+  return V;
+};
+
+// https://webidl.spec.whatwg.org/#BufferSource
+converters.BufferSource = (V, opts = kEmptyObject) => {
+  if (ArrayBufferIsView(V)) {
+    if (isSharedArrayBuffer(getDataViewOrTypedArrayBuffer(V))) {
+      throw makeException(
+        'is a view on a SharedArrayBuffer, which is not allowed.',
+        opts);
+    }
+
+    return V;
+  }
+
+  if (!isArrayBuffer(V)) {
+    throw makeException(
+      'is not instance of ArrayBuffer, Buffer, TypedArray, or DataView.',
+      opts);
+  }
+
+  return V;
+};
 
 module.exports = {
   type,

diff --git a/lib/internal/webstreams/readablestream.js b/lib/internal/webstreams/readablestream.js
@@ -48,6 +48,7 @@ const {
 const {
   isArrayBufferView,
   isDataView,
+  isSharedArrayBuffer,
 } = require('internal/util/types');
 
 const {
@@ -988,6 +989,15 @@ class ReadableStreamBYOBReader {
 
     const viewByteLength = ArrayBufferViewGetByteLength(view);
     const viewBuffer = ArrayBufferViewGetBuffer(view);
+
+    if (isSharedArrayBuffer(viewBuffer)) {
+      throw new ERR_INVALID_ARG_VALUE(
+        'view',
+        view,
+        'must not be backed by a SharedArrayBuffer',
+      );
+    }
+
     const viewBufferByteLength = ArrayBufferPrototypeGetByteLength(viewBuffer);
 
     if (viewByteLength === 0 || viewBufferByteLength === 0) {
@@ -1197,6 +1207,15 @@ class ReadableByteStreamController {
     validateBuffer(chunk);
     const chunkByteLength = ArrayBufferViewGetByteLength(chunk);
     const chunkBuffer = ArrayBufferViewGetBuffer(chunk);
+
+    if (isSharedArrayBuffer(chunkBuffer)) {
+      throw new ERR_INVALID_ARG_VALUE(
+        'chunk',
+        chunk,
+        'must not be backed by a SharedArrayBuffer',
+      );
+    }
+
     const chunkBufferByteLength = ArrayBufferPrototypeGetByteLength(chunkBuffer);
     if (chunkByteLength === 0 || chunkBufferByteLength === 0) {
       throw new ERR_INVALID_STATE.TypeError(

diff --git a/test/parallel/test-webapi-sharedarraybuffer-rejection.js b/test/parallel/test-webapi-sharedarraybuffer-rejection.js
@@ -0,0 +1,165 @@
+'use strict';
+// Flags: --expose-internals
+const common = require('../common');
+const assert = require('assert');
+const test = require('node:test');
+const { ReadableStream } = require('stream/web');
+
+const sab = new SharedArrayBuffer(8);
+const sabView = new Uint8Array(sab);
+const sabDataView = new DataView(sab);
+
+// -- ReadableStreamBYOBReader.read() --
+
+test('ReadableStreamBYOBReader.read() rejects SAB-backed Uint8Array', async () => {
+  const rs = new ReadableStream({
+    type: 'bytes',
+    pull(controller) {
+      controller.enqueue(new Uint8Array([1, 2, 3]));
+    },
+  });
+  const reader = rs.getReader({ mode: 'byob' });
+  await assert.rejects(
+    reader.read(new Uint8Array(sab)),
+    { code: 'ERR_INVALID_ARG_VALUE' },
+  );
+  reader.releaseLock();
+});
+
+test('ReadableStreamBYOBReader.read() rejects SAB-backed DataView', async () => {
+  const rs = new ReadableStream({
+    type: 'bytes',
+    pull(controller) {
+      controller.enqueue(new Uint8Array([1, 2, 3]));
+    },
+  });
+  const reader = rs.getReader({ mode: 'byob' });
+  await assert.rejects(
+    reader.read(sabDataView),
+    { code: 'ERR_INVALID_ARG_VALUE' },
+  );
+  reader.releaseLock();
+});
+
+test('ReadableStreamBYOBReader.read() accepts regular view', async () => {
+  const rs = new ReadableStream({
+    type: 'bytes',
+    pull(controller) {
+      controller.enqueue(new Uint8Array([1, 2, 3]));
+    },
+  });
+  const reader = rs.getReader({ mode: 'byob' });
+  const { value, done } = await reader.read(new Uint8Array(3));
+  assert.strictEqual(done, false);
+  assert.deepStrictEqual(value, new Uint8Array([1, 2, 3]));
+  reader.releaseLock();
+});
+
+// -- ReadableByteStreamController.enqueue() --
+
+test('ReadableByteStreamController.enqueue() rejects SAB-backed Uint8Array', async () => {
+  const sabForEnqueue = new SharedArrayBuffer(4);
+  const sabViewForEnqueue = new Uint8Array(sabForEnqueue);
+  sabViewForEnqueue[0] = 42;
+
+  const rs = new ReadableStream({
+    type: 'bytes',
+    pull: common.mustCall((controller) => {
+      assert.throws(
+        () => controller.enqueue(sabViewForEnqueue),
+        { code: 'ERR_INVALID_ARG_VALUE' },
+      );
+      controller.enqueue(new Uint8Array([1]));
+    }),
+  });
+  const reader = rs.getReader();
+  const { value } = await reader.read();
+  assert.deepStrictEqual(value, new Uint8Array([1]));
+  reader.releaseLock();
+});
+
+test('ReadableByteStreamController.enqueue() rejects SAB-backed DataView', async () => {
+  const sabForDv = new SharedArrayBuffer(4);
+  const dvForEnqueue = new DataView(sabForDv);
+
+  const rs = new ReadableStream({
+    type: 'bytes',
+    pull: common.mustCall((controller) => {
+      assert.throws(
+        () => controller.enqueue(dvForEnqueue),
+        { code: 'ERR_INVALID_ARG_VALUE' },
+      );
+      controller.enqueue(new Uint8Array([2]));
+    }),
+  });
+  const reader = rs.getReader();
+  const { value } = await reader.read();
+  assert.deepStrictEqual(value, new Uint8Array([2]));
+  reader.releaseLock();
+});
+
+// -- SharedWebIDL converters --
+
+const { converters } = require('internal/webidl');
+
+test('webidl converters.BufferSource rejects SharedArrayBuffer', () => {
+  assert.throws(
+    () => converters.BufferSource(sab),
+    { code: 'ERR_INVALID_ARG_TYPE' },
+  );
+});
+
+test('webidl converters.BufferSource rejects SAB-backed Uint8Array', () => {
+  assert.throws(
+    () => converters.BufferSource(sabView),
+    { code: 'ERR_INVALID_ARG_TYPE' },
+  );
+});
+
+test('webidl converters.BufferSource rejects SAB-backed DataView', () => {
+  assert.throws(
+    () => converters.BufferSource(sabDataView),
+    { code: 'ERR_INVALID_ARG_TYPE' },
+  );
+});
+
+test('webidl converters.BufferSource accepts ArrayBuffer', () => {
+  const ab = new ArrayBuffer(4);
+  assert.strictEqual(converters.BufferSource(ab), ab);
+});
+
+test('webidl converters.BufferSource accepts regular TypedArray', () => {
+  const ta = new Uint8Array(4);
+  assert.strictEqual(converters.BufferSource(ta), ta);
+});
+
+test('webidl converters.ArrayBufferView rejects SAB-backed Uint8Array', () => {
+  assert.throws(
+    () => converters.ArrayBufferView(sabView),
+    { code: 'ERR_INVALID_ARG_TYPE' },
+  );
+});
+
+test('webidl converters.ArrayBufferView rejects SAB-backed DataView', () => {
+  assert.throws(
+    () => converters.ArrayBufferView(sabDataView),
+    { code: 'ERR_INVALID_ARG_TYPE' },
+  );
+});
+
+test('webidl converters.ArrayBufferView rejects non-view', () => {
+  assert.throws(
+    () => converters.ArrayBufferView('not a view'),
+    { code: 'ERR_INVALID_ARG_TYPE' },
+  );
+});
+
+test('webidl converters.ArrayBufferView accepts regular Uint8Array', () => {
+  const ta = new Uint8Array(4);
+  assert.strictEqual(converters.ArrayBufferView(ta), ta);
+});
+
+test('webidl converters.ArrayBufferView accepts regular DataView', () => {
+  const dv = new DataView(new ArrayBuffer(4));
+  assert.strictEqual(converters.ArrayBufferView(dv), dv);
+});