diff --git a/Gemfile.lock b/Gemfile.lock
index 81719a3..627cb7e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -21,7 +21,7 @@ GEM
     json (1.8.3)
     minitest (5.8.4)
     multi_json (1.11.2)
-    rack (1.6.4)
+    rack (1.6.13)
     rack-protection (1.5.3)
       rack
     rack-test (0.6.3)