diff --git a/Gemfile.lock b/Gemfile.lock
index 3606f2f..4b26e2e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -80,7 +80,7 @@ GEM
       httpclient (~> 2.4)
       multi_json (~> 1.0)
       signature (~> 0.1.6)
-    rack (1.5.2)
+    rack (1.5.5)
     rack-test (0.6.2)
       rack (>= 1.0)
     rails (4.1.6)