diff --git a/packages/void/src/runtime/env-public.ts b/packages/void/src/runtime/env-public.ts
index dcb57b1f8..ff8ca3a75 100644
--- a/packages/void/src/runtime/env-public.ts
+++ b/packages/void/src/runtime/env-public.ts
@@ -252,7 +252,8 @@ function readKey(key: string): unknown {
   if (!registry.schema) {
     return rawValue;
   }
-  const validator = registry.schema[key];
+  // `env.hasOwnProperty` and the like come from Object.prototype, not from the schema.
+  const validator = Object.hasOwn(registry.schema, key) ? registry.schema[key] : undefined;
   if (!validator) {
     return rawValue;
   }
diff --git a/packages/void/test/unit/env-schema.test.ts b/packages/void/test/unit/env-schema.test.ts
index 890b9a81d..dd213cce1 100644
--- a/packages/void/test/unit/env-schema.test.ts
+++ b/packages/void/test/unit/env-schema.test.ts
@@ -127,6 +127,15 @@ describe('defineEnv + env proxy', () => {
     });
   });
 
+  it('passes through Object.prototype members without validation', () => {
+    defineEnv({ STRIPE_KEY: string() });
+    withRuntimeEnv({ STRIPE_KEY: 'sk' }, () => {
+      expect(env.hasOwnProperty).toBe(Object.prototype.hasOwnProperty);
+      expect(env.constructor).toBe(Object);
+      expect(String(env)).toBe('[object Object]');
+    });
+  });
+
   it('caches validated values per env identity (no re-validation)', () => {
     let calls = 0;
     const inner = string();