diff --git a/Gemfile b/Gemfile
index 7e41b4d8..bc036939 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,7 +10,7 @@ group :development do
 
   gem "ruby_memcheck", "2.3.0" if Gem::Platform.local.os == "linux"
 
-  gem "rdoc", "6.6.2"
+  gem "rdoc", "6.6.3.1"
 
   gem "rubocop", "1.59.0", require: false
   gem "rubocop-minitest", "0.34.5", require: false