diff --git a/Gemfile.lock b/Gemfile.lock
index 970c5af..1a173dc 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -30,7 +30,7 @@ GEM
     minitest (5.9.1)
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.3)
+    rack (2.2.3.1)
     rack-protection (2.2.0)
       rack
     rack-test (0.6.3)