diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
index 7399f6fab2..a0efab6b5b 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
@@ -97,7 +97,7 @@ class Configuration implements ConfigurationInterface
                     ->enumPrototype()
                         ->values([
                             'forwarded',
-                            'x-forwarded-for', 'x-forwarded-host', 'x-forwarded-proto', 'x-forwarded-port',
+                            'x-forwarded-for', 'x-forwarded-host', 'x-forwarded-proto', 'x-forwarded-port', 'x-forwarded-prefix',
                         ])
                     ->end()
                 ->end()
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
index ac69dfd525..c6cd60cc32 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
@@ -2305,6 +2305,7 @@ class FrameworkExtension extends Extension
                 case 'x-forwarded-host': $trustedHeaders |= Request::HEADER_X_FORWARDED_HOST; break;
                 case 'x-forwarded-proto': $trustedHeaders |= Request::HEADER_X_FORWARDED_PROTO; break;
                 case 'x-forwarded-port': $trustedHeaders |= Request::HEADER_X_FORWARDED_PORT; break;
+                case 'x-forwarded-prefix': $trustedHeaders |= Request::HEADER_X_FORWARDED_PREFIX; break;
             }
         }