diff --git a/simple-app-ruby/Gemfile.lock b/simple-app-ruby/Gemfile.lock
index e85d694..aaf50e8 100644
--- a/simple-app-ruby/Gemfile.lock
+++ b/simple-app-ruby/Gemfile.lock
@@ -3,7 +3,7 @@ GEM
   specs:
     mustermann (2.0.2)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.4)
+    rack (2.2.8.1)
     rack-protection (2.2.3)
       rack
     ruby2_keywords (0.0.5)