diff --git a/src/Symfony/Component/Runtime/SymfonyRuntime.php b/src/Symfony/Component/Runtime/SymfonyRuntime.php
index 9df2f5ca4b7b3..f75b917e517cd 100644
--- a/src/Symfony/Component/Runtime/SymfonyRuntime.php
+++ b/src/Symfony/Component/Runtime/SymfonyRuntime.php
@@ -103,7 +103,8 @@ public function __construct(array $options = [])
             $options['debug'] ?? $options['debug'] = '1' === $_SERVER['APP_DEBUG'];
             $options['disable_dotenv'] = true;
         } else {
-            $_SERVER['APP_ENV'] ?? $_SERVER['APP_ENV'] = 'dev';
+            $_SERVER['APP_ENV'] ?? $_SERVER['APP_ENV'] = $_ENV['APP_ENV'] ?? 'dev';
+            $_SERVER['APP_DEBUG'] ?? $_SERVER['APP_DEBUG'] = $_ENV['APP_DEBUG'] ?? !\in_array($_SERVER['APP_ENV'], (array) ($options['prod_envs'] ?? ['prod']), true);
         }
 
         $options['error_handler'] ?? $options['error_handler'] = SymfonyErrorHandler::class;