diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4191c9d0f..6f39278db 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
     * Fixed `$grav['route']` from being modified when the route instance gets modified
     * Fixed Assets options array mixed with standalone priority [#2477](https://github.com/getgrav/grav/issues/2477)
     * Fix for `avatar_url` provided by 3rd party providers
+    * Fixed non standard `lang` code lengths in `Utils` and `Session` detection
 
 # v1.6.8
 ## 04/23/2019
diff --git a/system/src/Grav/Common/Language/Language.php b/system/src/Grav/Common/Language/Language.php
index cbc1b5d1b..81abbc11a 100644
--- a/system/src/Grav/Common/Language/Language.php
+++ b/system/src/Grav/Common/Language/Language.php
@@ -104,6 +104,11 @@ class Language
     public function getAvailable()
     {
         $languagesArray = $this->languages; //Make local copy
+
+        $languagesArray = array_map(function($value) {
+            return preg_quote($value);
+        }, $languagesArray);
+
         sort($languagesArray);
 
         return implode('|', array_reverse($languagesArray));
diff --git a/system/src/Grav/Common/Service/SessionServiceProvider.php b/system/src/Grav/Common/Service/SessionServiceProvider.php
index 96cbec97f..856ec3596 100644
--- a/system/src/Grav/Common/Service/SessionServiceProvider.php
+++ b/system/src/Grav/Common/Service/SessionServiceProvider.php
@@ -13,6 +13,7 @@ use Grav\Common\Config\Config;
 use Grav\Common\Debugger;
 use Grav\Common\Session;
 use Grav\Common\Uri;
+use Grav\Common\Utils;
 use Pimple\Container;
 use Pimple\ServiceProviderInterface;
 use RocketTheme\Toolbox\Session\Message;
@@ -55,8 +56,7 @@ class SessionServiceProvider implements ServiceProviderInterface
                 $current_route = str_replace(Uri::filterPath($uri->rootUrl(false)), '', parse_url($uri->url(true), PHP_URL_PATH));
 
                 // Check no language, simple language prefix (en) and region specific language prefix (en-US).
-                $pos = strpos($current_route, $base);
-                if ($pos === 0 || $pos === 3 || $pos === 6) {
+                if (Utils::startsWith($current_route, $base) || Utils::pathPrefixedByLangCode($current_route)) {
                     $cookie_lifetime = $config->get('plugins.admin.session.timeout', 1800);
                     $enabled = $is_admin = true;
                 }
diff --git a/system/src/Grav/Common/Utils.php b/system/src/Grav/Common/Utils.php
index c254009e5..4beaeac4c 100644
--- a/system/src/Grav/Common/Utils.php
+++ b/system/src/Grav/Common/Utils.php
@@ -975,6 +975,7 @@ abstract class Utils
      * @param string $string The path
      *
      * @return bool
+     *
      */
     public static function pathPrefixedByLangCode($string)
     {
@@ -983,8 +984,13 @@ abstract class Utils
         }
 
         $languages_enabled = Grav::instance()['config']->get('system.languages.supported', []);
+        $parts = explode('/', trim($string, '/'));
 
-        return $string[0] === '/' && $string[3] === '/' && \in_array(substr($string, 1, 2), $languages_enabled, true);
+        if (count($parts) > 0 && in_array($parts[0], $languages_enabled)) {
+            return true;
+        }
+
+        return false;
     }
 
     /**