diff --git a/activerecord-session_store.gemspec b/activerecord-session_store.gemspec
index efe846d..d186c77 100644
--- a/activerecord-session_store.gemspec
+++ b/activerecord-session_store.gemspec
@@ -24,6 +24,7 @@ Gem::Specification.new do |s|
   s.add_dependency('railties', '>= 6.1')
   s.add_dependency('rack', '>= 2.0.8', '< 3')
   s.add_dependency('multi_json', '~> 1.11', '>= 1.11.2')
+  s.add_dependency('cgi', '>= 0.3.6')
 
   s.add_development_dependency('sqlite3')
 end