diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 6ce3c4c0..f9e4787e 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -1,3 +1,3 @@
 # Make sure RUBY_VERSION matches the Ruby version in .ruby-version
-ARG RUBY_VERSION=3.2.9
+ARG RUBY_VERSION=3.2.9@sha256:506102b812660a912d3a88775130525ad1663ad7e1eff57a38e41fcd2749bc87
 FROM ghcr.io/rails/devcontainer/images/ruby:$RUBY_VERSION