diff --git a/.github/ISSUE_TEMPLATE/2.server_bug_report.yml b/.github/ISSUE_TEMPLATE/2.server_bug_report.yml
index 99ec9cf146f..ec3a52689d4 100644
--- a/.github/ISSUE_TEMPLATE/2.server_bug_report.yml
+++ b/.github/ISSUE_TEMPLATE/2.server_bug_report.yml
@@ -59,7 +59,7 @@ body:
         Any additional technical details you may have, like logs or error traces
       value: |
         If this is happening on your own Mastodon server, please fill out those:
-        - Ruby version: (from `ruby --version`, eg. v3.4.4)
+        - Ruby version: (from `ruby --version`, eg. v3.4.9)
         - Node.js version: (from `node --version`, eg. v22.16.0)
     validations:
       required: false
diff --git a/.github/ISSUE_TEMPLATE/3.troubleshooting.yml b/.github/ISSUE_TEMPLATE/3.troubleshooting.yml
index 004e74bf42e..5278933ecef 100644
--- a/.github/ISSUE_TEMPLATE/3.troubleshooting.yml
+++ b/.github/ISSUE_TEMPLATE/3.troubleshooting.yml
@@ -61,7 +61,7 @@ body:
       value: |
         Please at least include those informations:
         - Operating system: (eg. Ubuntu 24.04.2)
-        - Ruby version: (from `ruby --version`, eg. v3.4.4)
+        - Ruby version: (from `ruby --version`, eg. v3.4.9)
         - Node.js version: (from `node --version`, eg. v22.16.0)
     validations:
       required: false
diff --git a/.github/actions/setup-ruby/action.yml b/.github/actions/setup-ruby/action.yml
index 0085aa875cb..fed79add6d8 100644
--- a/.github/actions/setup-ruby/action.yml
+++ b/.github/actions/setup-ruby/action.yml
@@ -17,7 +17,7 @@ runs:
         sudo apt-get install -y libicu-dev libidn11-dev libvips42 ${{ inputs.additional-system-dependencies }}
 
     - name: Set up Ruby
-      uses: ruby/setup-ruby@09a7688d3b55cf0e976497ff046b70949eeaccfd # v1
+      uses: ruby/setup-ruby@4eb9f110bac952a8b68ecf92e3b5c7a987594ba6 # v1
       with:
         ruby-version: ${{ inputs.ruby-version }}
         bundler-cache: true
diff --git a/.github/workflows/bundler-audit.yml b/.github/workflows/bundler-audit.yml
index f3a97f8a2ea..b1e8d406e25 100644
--- a/.github/workflows/bundler-audit.yml
+++ b/.github/workflows/bundler-audit.yml
@@ -31,7 +31,7 @@ jobs:
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Set up Ruby
-        uses: ruby/setup-ruby@09a7688d3b55cf0e976497ff046b70949eeaccfd # v1
+        uses: ruby/setup-ruby@4eb9f110bac952a8b68ecf92e3b5c7a987594ba6 # v1
         with:
           bundler-cache: true
 
diff --git a/.github/workflows/lint-haml.yml b/.github/workflows/lint-haml.yml
index 46cf1c25c10..6cc212180a8 100644
--- a/.github/workflows/lint-haml.yml
+++ b/.github/workflows/lint-haml.yml
@@ -36,7 +36,7 @@ jobs:
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Set up Ruby
-        uses: ruby/setup-ruby@09a7688d3b55cf0e976497ff046b70949eeaccfd # v1
+        uses: ruby/setup-ruby@4eb9f110bac952a8b68ecf92e3b5c7a987594ba6 # v1
         with:
           bundler-cache: true
 
diff --git a/.github/workflows/lint-ruby.yml b/.github/workflows/lint-ruby.yml
index f99362895a5..216618f4e56 100644
--- a/.github/workflows/lint-ruby.yml
+++ b/.github/workflows/lint-ruby.yml
@@ -38,7 +38,7 @@ jobs:
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Set up Ruby
-        uses: ruby/setup-ruby@09a7688d3b55cf0e976497ff046b70949eeaccfd # v1
+        uses: ruby/setup-ruby@4eb9f110bac952a8b68ecf92e3b5c7a987594ba6 # v1
         with:
           bundler-cache: true
 
diff --git a/.ruby-version b/.ruby-version
index 7921bd0c892..7bcbb3808b5 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.4.8
+3.4.9
diff --git a/Dockerfile b/Dockerfile
index c06bc84a339..6a191b7e851 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,7 +13,7 @@ ARG BASE_REGISTRY="docker.io"
 
 # Ruby image to use for base image, change with [--build-arg RUBY_VERSION="3.4.x"]
 # renovate: datasource=docker depName=docker.io/ruby
-ARG RUBY_VERSION="3.4.8"
+ARG RUBY_VERSION="3.4.9"
 # # Node.js version to use in base image, change with [--build-arg NODE_MAJOR_VERSION="22"]
 # renovate: datasource=node-version depName=node
 ARG NODE_MAJOR_VERSION="24"
diff --git a/Gemfile.lock b/Gemfile.lock
index 5ab80abb8c5..6ecf05eff10 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1097,7 +1097,7 @@ DEPENDENCIES
   xorcist (~> 1.1)
 
 RUBY VERSION
-  ruby 3.4.8
+  ruby 3.4.9
 
 BUNDLED WITH
   4.0.8