diff --git a/library/Icinga/Web/Session/PhpSession.php b/library/Icinga/Web/Session/PhpSession.php
index e00544cf9b..e4df067047 100644
--- a/library/Icinga/Web/Session/PhpSession.php
+++ b/library/Icinga/Web/Session/PhpSession.php
@@ -94,7 +94,9 @@ public function __construct(array $options = null)
      */
     protected function open()
     {
-        session_name($this->sessionName);
+        if (!isset($_SESSION)) {
+            session_name($this->sessionName);
+        }
 
         if ($this->hasBeenTouched) {
             $cacheLimiter = ini_get('session.cache_limiter');