diff --git a/styleguide/Gemfile.lock b/styleguide/Gemfile.lock
index 4fa6c6e3..f9cc6297 100644
--- a/styleguide/Gemfile.lock
+++ b/styleguide/Gemfile.lock
@@ -113,7 +113,7 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.5)
-    rack (2.2.3)
+    rack (2.2.6.4)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)