diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 9f64932..e843287 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -30,6 +30,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Security
+
+- **`allow_unauthenticated` refused in production.** The switch opens the layout admin to anonymous users; the
+  container now refuses to compile with it in the `prod` environment or in any non-debug kernel outside `test*`
+  environments (as ContactFormBundle).
+
 ## [1.8.1] - 2026-10-28
 
 Security: the admin controllers are guarded by class, so a route name_prefix no longer bypasses the access check. See [UPGRADING](UPGRADING.md#to-181).
diff --git a/src/DependencyInjection/NowoPageLayoutKitExtension.php b/src/DependencyInjection/NowoPageLayoutKitExtension.php
index ac69d3b..32377f8 100644
--- a/src/DependencyInjection/NowoPageLayoutKitExtension.php
+++ b/src/DependencyInjection/NowoPageLayoutKitExtension.php
@@ -25,6 +25,7 @@
 use function array_key_exists;
 use function is_array;
 use function is_string;
+use function str_starts_with;
 
 /**
  * Loads PageLayoutKit services and publishes configuration parameters.
@@ -117,6 +118,7 @@ public function getAlias(): string
     private function registerAccessChecker(ContainerBuilder $container, array $security): void
     {
         if ($security['allow_unauthenticated']) {
+            $this->refuseAllowUnauthenticatedInProduction($container);
             $id = 'nowo_page_layout_kit.access_checker.allow_all';
             $container->setDefinition($id, new Definition(AllowAllPageLayoutKitAccessChecker::class));
             $container->setAlias(PageLayoutKitAccessCheckerInterface::class, $id);
@@ -194,4 +196,19 @@ private function isSecurityBundleAvailable(ContainerBuilder $container): bool
 
         return isset($bundles['SecurityBundle']);
     }
+
+    /**
+     * `allow_unauthenticated` opens the layout admin to anonymous users: a dev / demo switch, refused in the prod
+     * environment and in any non-debug kernel outside the test environments (test*), as in ContactFormBundle.
+     */
+    private function refuseAllowUnauthenticatedInProduction(ContainerBuilder $container): void
+    {
+        $environment = $container->hasParameter('kernel.environment') ? $container->getParameter('kernel.environment') : '';
+        $environment = is_string($environment) ? $environment : '';
+        $debug       = $container->hasParameter('kernel.debug') ? (bool) $container->getParameter('kernel.debug') : true;
+
+        if ($environment === 'prod' || (!$debug && !str_starts_with($environment, 'test'))) {
+            throw new LogicException('nowo_page_layout_kit.security.allow_unauthenticated is a dev/demo switch: it opens the layout admin to anonymous users and is refused in the prod environment and in non-debug kernels (test* environments excepted).');
+        }
+    }
 }
diff --git a/tests/Unit/DependencyInjection/NowoPageLayoutKitExtensionTest.php b/tests/Unit/DependencyInjection/NowoPageLayoutKitExtensionTest.php
index 0c9fd50..72a0365 100644
--- a/tests/Unit/DependencyInjection/NowoPageLayoutKitExtensionTest.php
+++ b/tests/Unit/DependencyInjection/NowoPageLayoutKitExtensionTest.php
@@ -20,6 +20,7 @@
 use Nowo\PageLayoutKitBundle\Security\PageLayoutProtection;
 use Nowo\PageLayoutKitBundle\Security\PageLayoutProtectionConfig;
 use Nowo\PageLayoutKitBundle\Service\PageBlockMigrator;
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Symfony\Bundle\SecurityBundle\SecurityBundle;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
@@ -98,6 +99,33 @@ public function testPrependPublishesTheDefaultFormKitProfileWhenMissing(): void
         (new NowoPageLayoutKitExtension())->prepend($container);
     }
 
+    /**
+     * @return iterable<string, array{string, bool, bool}>
+     */
+    public static function allowUnauthenticatedKernels(): iterable
+    {
+        yield 'dev debug' => ['dev', true, true];
+        yield 'test without debug' => ['test', false, true];
+        yield 'prod' => ['prod', true, false];
+        yield 'staging without debug' => ['staging', false, false];
+    }
+
+    #[DataProvider('allowUnauthenticatedKernels')]
+    public function testAllowUnauthenticatedIsRefusedInProduction(string $environment, bool $debug, bool $allowed): void
+    {
+        $container = new ContainerBuilder();
+        $container->setParameter('kernel.environment', $environment);
+        $container->setParameter('kernel.debug', $debug);
+        if (!$allowed) {
+            $this->expectException(LogicException::class);
+            $this->expectExceptionMessage('dev/demo switch');
+        }
+
+        (new NowoPageLayoutKitExtension())->load([['security' => ['allow_unauthenticated' => true]]], $container);
+
+        self::assertTrue($container->hasDefinition('nowo_page_layout_kit.access_checker.allow_all'));
+    }
+
     public function testLoadPublishesParametersAndRegistersAllowAllAccessChecker(): void
     {
         $container = new ContainerBuilder();