diff --git a/Gemfile.lock b/Gemfile.lock
index 7f1c75342a..7e51c8b861 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -50,7 +50,7 @@ GEM
     nokogiri (1.6.6.2)
       mini_portile (~> 0.6.0)
     open4 (1.3.4)
-    rack (1.5.2)
+    rack (1.5.5)
     rack-protection (1.5.3)
       rack
     rack-test (0.6.3)