diff --git a/ruby/Gemfile.lock b/ruby/Gemfile.lock
index 0f6f5fc..a72eb93 100644
--- a/ruby/Gemfile.lock
+++ b/ruby/Gemfile.lock
@@ -4,7 +4,7 @@ GEM
     multi_json (1.15.0)
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.3)
+    rack (2.2.6.4)
     rack-protection (2.1.0)
       rack
     ruby2_keywords (0.0.5)