diff --git a/Gemfile.lock b/Gemfile.lock
index ee1a9df..f83099c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,7 +7,7 @@ GEM
     mqtt (0.5.0)
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.3)
+    rack (2.2.6.4)
     rack-protection (2.1.0)
       rack
     rack-test (1.1.0)