diff --git a/__tests__/CWE-1321.test.ts b/__tests__/CWE-1321.test.ts
new file mode 100644
index 0000000..8d9a6e3
--- /dev/null
+++ b/__tests__/CWE-1321.test.ts
@@ -0,0 +1,16 @@
+import plist from "../src";
+
+/** @see https://cwe.mitre.org/data/definitions/1321.html */
+
+describe("CWE-1321", () => {
+  it("filters out unsafe properties", () => {
+    const unsafeDoc = { __proto__: 42, foo: "bar" };
+    const safeDoc = plist.parse(plist.stringify(unsafeDoc));
+
+    expect(safeDoc).toMatchInlineSnapshot(`
+      Object {
+        "foo": "bar",
+      }
+    `);
+  });
+});