From 7fda04da9fa681af1ac6953d629086e54ccf104d Mon Sep 17 00:00:00 2001
From: Oskar Eichler <oskar@songstats.com>
Date: Sun, 30 Aug 2026 10:33:31 +0200
Subject: [PATCH] Reject boxed Symbols in structuredClone

---
 .../structuredClone/__tests__/structuredClone-itest.js     | 1 +
 .../src/private/webapis/structuredClone/structuredClone.js | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/packages/react-native/src/private/webapis/structuredClone/__tests__/structuredClone-itest.js b/packages/react-native/src/private/webapis/structuredClone/__tests__/structuredClone-itest.js
index 402e055048d..c21922263c6 100644
--- a/packages/react-native/src/private/webapis/structuredClone/__tests__/structuredClone-itest.js
+++ b/packages/react-native/src/private/webapis/structuredClone/__tests__/structuredClone-itest.js
@@ -86,6 +86,7 @@ describe('structuredClone', () => {
 
   it('throws with symbols, functions, WeakMap, WeakSet, Promise', () => {
     expectDataCloneError(() => structuredClone(Symbol()));
+    expectDataCloneError(() => structuredClone(Object(Symbol())));
     expectDataCloneError(() => structuredClone(() => {}));
     expectDataCloneError(() => structuredClone(new WeakMap()));
     expectDataCloneError(() => structuredClone(new WeakSet()));
diff --git a/packages/react-native/src/private/webapis/structuredClone/structuredClone.js b/packages/react-native/src/private/webapis/structuredClone/structuredClone.js
index 89a7f90725b..d6f0a486ebd 100644
--- a/packages/react-native/src/private/webapis/structuredClone/structuredClone.js
+++ b/packages/react-native/src/private/webapis/structuredClone/structuredClone.js
@@ -166,6 +166,13 @@ function structuredCloneInternal<T>(value: T): T {
     return result;
   }
 
+  if (value instanceof Symbol) {
+    throw new DOMException(
+      "Failed to execute 'structuredClone' on 'Window': Symbol object could not be cloned.",
+      'DataCloneError',
+    );
+  }
+
   // Known non-serializable objects.
   if (isNonSerializableObject(value) || isPlatformObject(value)) {
     throw new DOMException(