diff --git a/.ruby-version b/.ruby-version
index a2cec7aff4..7919852fe1 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-4.0.8
+4.0.9
diff --git a/.tool-versions b/.tool-versions
index 88e25b1ae7..8fc8276c19 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -1,2 +1,2 @@
-ruby 4.0.8
+ruby 4.0.9
 nodejs 26.12.1
diff --git a/Dockerfile b/Dockerfile
index e7bc26f566..72f88db2bc 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:4.0.7
+FROM ruby:4.0.8
 ENV LANG=C.UTF-8
 ENV ENABLE_SERVICE_WORKER=true
 
diff --git a/Dockerfile-alpine b/Dockerfile-alpine
index 9582f54bc8..f18f032081 100644
--- a/Dockerfile-alpine
+++ b/Dockerfile-alpine
@@ -1,4 +1,4 @@
-FROM ruby:4.0.7-alpine
+FROM ruby:4.0.8-alpine
 
 ENV LANG=C.UTF-8
 ENV ENABLE_SERVICE_WORKER=true
diff --git a/Gemfile b/Gemfile
index 2b5205801f..18d54ed594 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
-ruby '4.0.8'
+ruby '4.0.9'
 
 gem 'activesupport', require: false
 gem 'html-pipeline', '~> 2.14'
diff --git a/Gemfile.lock b/Gemfile.lock
index 5aee85557e..16241f0bac 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -473,7 +473,7 @@ CHECKSUMS
   zeitwerk (2.8.3) sha256=2c85125a8467ce069e20123d1e709a08955c9d29c118c25b46b7b7fafdbb92e5
 
 RUBY VERSION
-  ruby 4.0.8
+  ruby 4.0.9
 
 BUNDLED WITH
   4.0.12