diff --git a/chapter10/Gemfile.lock b/chapter10/Gemfile.lock
index c2f220b..a4d9fdb 100644
--- a/chapter10/Gemfile.lock
+++ b/chapter10/Gemfile.lock
@@ -4,7 +4,7 @@ GEM
     cgi (0.1.0)
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.3)
+    rack (2.2.6.4)
     rack-protection (2.0.8.1)
       rack
     ruby2_keywords (0.0.2)