diff --git a/Gemfile.lock b/Gemfile.lock
index 5f95e21..75a2bb0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -10,7 +10,7 @@ GEM
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
     public_suffix (4.0.6)
-    rack (2.2.3)
+    rack (2.2.6.4)
     rack-protection (2.1.0)
       rack
     rack-test (1.1.0)