3 files changed, 10 insertions, 2 deletions
diff --git a/guides/source/rails_on_rack.md b/guides/source/rails_on_rack.md
index 6780e7c0de..1627205b7b 100644
--- a/guides/source/rails_on_rack.md
+++ b/guides/source/rails_on_rack.md
@@ -126,6 +126,7 @@ use ActionDispatch::ContentSecurityPolicy::Middleware
 use Rack::Head
 use Rack::ConditionalGet
 use Rack::ETag
+use Rack::TempfileReaper
 run MyApp::Application.routes
 ```
 
@@ -300,6 +301,10 @@ Much of Action Controller's functionality is implemented as Middlewares. The fol
 
 * Adds ETag header on all String bodies. ETags are used to validate cache.
 
+**`Rack::TempfileReaper`**
+
+* Cleans up tempfiles used to buffer multipart requests.
+
 TIP: It's possible to use any of the above middlewares in your custom Rack stack.
 
 Resources
diff --git a/railties/lib/rails/application/default_middleware_stack.rb b/railties/lib/rails/application/default_middleware_stack.rb
index 0e79ba7da0..73c7defe7f 100644
--- a/railties/lib/rails/application/default_middleware_stack.rb
+++ b/railties/lib/rails/application/default_middleware_stack.rb
@@ -70,6 +70,7 @@ module Rails
           middleware.use ::Rack::Head
           middleware.use ::Rack::ConditionalGet
           middleware.use ::Rack::ETag, "no-cache"
+          middleware.use ::Rack::TempfileReaper
         end
       end
 
diff --git a/railties/test/application/middleware_test.rb b/railties/test/application/middleware_test.rb
index d59384e982..b9e4a9ccc0 100644
--- a/railties/test/application/middleware_test.rb
+++ b/railties/test/application/middleware_test.rb
@@ -45,7 +45,8 @@ module ApplicationTests
         "ActionDispatch::ContentSecurityPolicy::Middleware",
         "Rack::Head",
         "Rack::ConditionalGet",
-        "Rack::ETag"
+        "Rack::ETag",
+        "Rack::TempfileReaper"
       ], middleware
     end
 
@@ -69,7 +70,8 @@ module ApplicationTests
         "ActionDispatch::Callbacks",
         "Rack::Head",
         "Rack::ConditionalGet",
-        "Rack::ETag"
+        "Rack::ETag",
+        "Rack::TempfileReaper"
       ], middleware
     end