diff --git a/scripts/build/deps/webkit.ts b/scripts/build/deps/webkit.ts
index f84dd77e0e19..8ca6857967c7 100644
--- a/scripts/build/deps/webkit.ts
+++ b/scripts/build/deps/webkit.ts
@@ -3,7 +3,7 @@
  * for local mode. Override via `--webkit-version=<hash>` to test a branch.
  * From https://github.com/oven-sh/WebKit releases.
  */
-export const WEBKIT_VERSION = "549170099226f816a4b204ea1d8fa102fb79eefa";
+export const WEBKIT_VERSION = "autobuild-preview-pr-369-bce3c3e1";
 
 /**
  * WebKit (JavaScriptCore) — the JS engine.
diff --git a/test/js/bun/jsc/builtin-error-message.test.ts b/test/js/bun/jsc/builtin-error-message.test.ts
new file mode 100644
index 000000000000..8494ea2ac377
--- /dev/null
+++ b/test/js/bun/jsc/builtin-error-message.test.ts
@@ -0,0 +1,37 @@
+import { expect, test } from "bun:test";
+
+// TypeError messages thrown from JSC builtin JavaScript must not leak the
+// builtin's private @-prefixed identifiers (e.g. `@call`, `@getWrapForValidIteratorInternalField`)
+// into user-visible `error.message`. Release builds already suppress this by
+// omitting expression info for builtins; this test guards the ASSERT_ENABLED
+// path (debug / ASAN) where builtins do carry expression info.
+
+function messageOf(fn: () => unknown): string {
+  try {
+    fn();
+  } catch (e) {
+    return (e as Error).message;
+  }
+  throw new Error("expected fn to throw");
+}
+
+test("%WrapForValidIteratorPrototype%.next on a wrapped iterator with no next method", () => {
+  const msg = messageOf(() => Iterator.from({} as any).next());
+  expect(msg).not.toContain("@");
+  expect(msg).not.toContain("WrapForValidIterator");
+  expect(msg).toBe("undefined is not a function");
+});
+
+test("%WrapForValidIteratorPrototype%.return with a non-callable return", () => {
+  const msg = messageOf(() => Iterator.from({ next: () => ({ done: false, value: 1 }), return: 5 } as any).return());
+  expect(msg).not.toContain("@");
+  expect(msg).not.toContain("returnMethod");
+  expect(msg).toBe("5 is not a function");
+});
+
+test("Iterator.from with a non-callable Symbol.iterator", () => {
+  const msg = messageOf(() => Iterator.from({ [Symbol.iterator]: 5 } as any));
+  expect(msg).not.toContain("@");
+  expect(msg).not.toContain("method");
+  expect(msg).toBe("5 is not a function");
+});