Under certain circumstances response bodies will not be closed, for example a bug in a webserver or a bug in a Rack middleware. In the event a response is not notified of a close
, ActionDispatch::Executor
will not know to reset thread local state for the next request. This can lead to data being leaked to subsequent requests, especially when interacting with ActiveSupport::CurrentAttributes
.
Upgrading to the FIXED versions of Rails will ensure mitigation of this issue even in the context of a buggy webserver or middleware implementation.
This has been fixed in Rails 7.0.2.2, 6.1.4.6, 6.0.4.6, and 5.2.6.2.
Upgrading is highly recommended, but to work around this problem the following middleware can be used:
class GuardedExecutor < ActionDispatch::Executor
def call(env)
ensure_completed!
super
end
private
def ensure_completed!
@executor.new.complete! if @executor.active?
end
end
# Ensure the guard is inserted before ActionDispatch::Executor
Rails.application.configure do
config.middleware.swap ActionDispatch::Executor, GuardedExecutor, executor
end