diff --git a/Gemfile b/Gemfile
index 2a9d2060..cff34fa2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ group :default do
   if rack_version = ENV['RACK_VERSION']
     gem 'rack', rack_version
   else
-    gem 'rack', '~> 2.2.0'
+    gem 'rack', '~> 2.2.18'
   end
 end
 
diff --git a/Gemfile.lock b/Gemfile.lock
index bcf1f2d5..9ed3c0f3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,7 +6,7 @@ GEM
       rake
       thor (>= 0.14.0)
     diff-lcs (1.6.2)
-    rack (2.2.17)
+    rack (2.2.18)
     rake (13.3.0)
     rspec (3.13.1)
       rspec-core (~> 3.13.0)
@@ -32,6 +32,6 @@ PLATFORMS
 
 DEPENDENCIES
   appraisal
-  rack (~> 2.2.0)
+  rack (~> 2.2.18)
   rake (~> 13.3)
   rspec