diff --git a/actionpack/actionpack.gemspec b/actionpack/actionpack.gemspec
index ed5b7e1e93e5a..a5abe9be10e0d 100644
--- a/actionpack/actionpack.gemspec
+++ b/actionpack/actionpack.gemspec
@@ -23,6 +23,6 @@ Gem::Specification.new do |s|
   s.add_dependency('activemodel',   version)
   s.add_dependency('rack',          '~> 1.1.0')
   s.add_dependency('rack-test',     '~> 0.5.0')
-  s.add_dependency('rack-mount',    '~> 0.6.0')
+  s.add_dependency('rack-mount',    '~> 0.6.3')
   s.add_dependency('erubis',        '~> 2.6.5')
 end
diff --git a/railties/guides/source/initialization.textile b/railties/guides/source/initialization.textile
index 7df4f8f719a3d..a8c7ce08657ee 100644
--- a/railties/guides/source/initialization.textile
+++ b/railties/guides/source/initialization.textile
@@ -148,7 +148,7 @@ Here the only two gems we need are +rails+ and +sqlite3-ruby+, so it seems. This
 * mime-types-1.16.gem
 * polyglot-0.3.1.gem
 * rack-1.1.0.gem
-* rack-mount-0.6.1.gem
+* rack-mount-0.6.3.gem
 * rack-test-0.5.3.gem
 * rails-3.0.0.beta1.gem
 * railties-3.0.0.beta1.gem
@@ -4141,4 +4141,4 @@ The _activesupport/lib/active_support/ruby/shim.rb_ file requires methods that h
 
 For more information see the ActiveSupport Extensions guide TODO: link to relevant sections for each method.
 
-And "the REXML security fix detailed here":[http://weblog.rubyonrails.org/2008/8/23/dos-vulnerabilities-in-rexml]
\ No newline at end of file
+And "the REXML security fix detailed here":[http://weblog.rubyonrails.org/2008/8/23/dos-vulnerabilities-in-rexml]