diff --git a/Gemfile b/Gemfile
index f0e1edd..2bf5cad 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,6 +4,9 @@ gemspec
 
 # Runtime dependency
 if RUBY_VERSION >= '3.1'
+  if RUBY_VERSION < '3.2'
+    gem 'cgi', '0.3.6'
+  end
   gem 'rack', github: 'rack/rack'
 else
   gem 'rack', '~> 2.0'