diff --git a/lib/brakeman/checks/check_i18n_xss.rb b/lib/brakeman/checks/check_i18n_xss.rb
new file mode 100644
index 0000000000000000000000000000000000000000..5c31de6ed807f786bdc9d1bd9c6615baf540f446
--- /dev/null
+++ b/lib/brakeman/checks/check_i18n_xss.rb
@@ -0,0 +1,49 @@
+require 'brakeman/checks/base_check'
+
+class Brakeman::CheckI18nXSS < Brakeman::BaseCheck
+  Brakeman::Checks.add self
+
+  @description = "Checks for i18n XSS (CVE-2013-4491)"
+
+  def run_check
+    if (version_between? "3.0.6", "3.2.15" or version_between? "4.0.0", "4.0.1")# and not has_workaround?
+      message = "Rails #{tracker.config[:rails_version]} has an XSS vulnerability in i18n (CVE-2013-4491). Upgrade to Rails version "
+
+      i18n_gem = tracker.config[:gems] && tracker.config[:gems][:i18n]
+
+      if version_between? "3.0.6", "3.1.99" and version_before i18n_gem, "0.5.1"
+        message << "3.2.16 or i18n 0.5.1"
+      elsif version_between? "3.2.0", "4.0.1" and version_before i18n_gem, "0.6.6"
+        message << "4.0.2 or i18n 0.6.6"
+      else
+        return
+      end
+
+      warn :warning_type => "Cross Site Scripting",
+        :warning_code => :CVE_2013_4491,
+        :message => message,
+        :confidence => CONFIDENCE[:med],
+        :file => gemfile_or_environment,
+        :link_path => "https://groups.google.com/d/msg/ruby-security-ann/pLrh6DUw998/bLFEyIO4k_EJ"
+    end
+  end
+
+  def version_before gem_version, target
+    return true unless gem_version
+    gem_version.split('.').map(&:to_i).zip(target.split('.').map(&:to_i)).each do |gv, t|
+      if gv < t
+        return true
+      elsif gv > t
+        return false
+      end
+    end
+
+    false
+  end
+
+  def has_workaround?
+    tracker.check_initializers(:I18n, :const_defined?).any? do |match|
+      match.last.first_arg == s(:lit, :MissingTranslation)
+    end
+  end
+end
diff --git a/lib/brakeman/processors/gem_processor.rb b/lib/brakeman/processors/gem_processor.rb
index 66625ceb03417702ec44ac9889b9247b65de7ff0..d0471219aee2b687faca1c055073750eaeb6aff5 100644
--- a/lib/brakeman/processors/gem_processor.rb
+++ b/lib/brakeman/processors/gem_processor.rb
@@ -15,6 +15,7 @@ class Brakeman::GemProcessor < Brakeman::BaseProcessor
     if gem_lock
       get_rails_version gem_lock
       get_json_version gem_lock
+      get_i18n_version gem_lock
     elsif @tracker.config[:gems][:rails] =~ /(\d+.\d+.\d+)/
       @tracker.config[:rails_version] = $1
     end
@@ -61,4 +62,8 @@ class Brakeman::GemProcessor < Brakeman::BaseProcessor
     @tracker.config[:gems][:json] = get_version("json", gem_lock)
     @tracker.config[:gems][:json_pure] = get_version("json_pure", gem_lock)
   end
+
+  def get_i18n_version gem_lock
+    @tracker.config[:gems][:i18n] = get_version("i18n", gem_lock)
+  end
 end
diff --git a/lib/brakeman/warning_codes.rb b/lib/brakeman/warning_codes.rb
index 589272b50f2d679129377b72d949b57c948d2066..87044163f524e4ade241ce612378321d55572145 100644
--- a/lib/brakeman/warning_codes.rb
+++ b/lib/brakeman/warning_codes.rb
@@ -62,7 +62,8 @@ module Brakeman::WarningCodes
     :unsafe_symbol_creation => 59,
     :dangerous_attr_accessible => 60,
     :local_request_config => 61,
-    :detailed_exceptions => 62
+    :detailed_exceptions => 62,
+    :CVE_2013_4491 => 63,
   }
 
   def self.code name
diff --git a/test/apps/rails4/config/initializers/i18n.rb b/test/apps/rails4/config/initializers/i18n.rb
new file mode 100644
index 0000000000000000000000000000000000000000..d9b10bbad710d5c5a26fb239ae81046ab5fb9860
--- /dev/null
+++ b/test/apps/rails4/config/initializers/i18n.rb
@@ -0,0 +1,20 @@
+require 'i18n' 
+
+# Override exception handler to more carefully html-escape missing-key results. 
+class HtmlSafeI18nExceptionHandler 
+  Missing = I18n.const_defined?(:MissingTranslation) ? I18n::MissingTranslation : I18n::MissingTranslationData 
+
+  def initialize(original_exception_handler) 
+    @original_exception_handler = original_exception_handler 
+  end 
+
+  def call(exception, locale, key, options) 
+    if exception.is_a?(Missing) && options[:rescue_format] == :html 
+      keys = exception.keys.map { |k| Rack::Utils.escape_html k } 
+      key = keys.last.to_s.gsub('_', ' ').gsub(/\b('?[a-z])/) { $1.capitalize } 
+      %(<span class="translation_missing" title="translation missing: #{keys.join('.')}">#{key}</span>) 
+    else 
+      @original_exception_handler.call(exception, locale, key, options) 
+    end 
+  end 
+end 
diff --git a/test/tests/only_files_option.rb b/test/tests/only_files_option.rb
index dd86f6f62d2f0932ee6a790dba12ecb87ab04221..1dc012f23e18bae81be8600de35fe13d1b3ff1e8 100644
--- a/test/tests/only_files_option.rb
+++ b/test/tests/only_files_option.rb
@@ -53,4 +53,13 @@ class OnlyFilesOptionTests < Test::Unit::TestCase
       :file => /sanitized\.html\.erb/
   end
 
+  def test_i18n_xss_CVE_2013_4491
+    assert_warning :type => :warning,
+      :warning_code => 63,
+      :fingerprint => "de0e11056b9f9af7b8570d5354185cd7e17a18cc61d627555fe4adfff00fb447",
+      :warning_type => "Cross Site Scripting",
+      :message => /^Rails\ 3\.2\.9\.rc2\ has\ an\ XSS\ vulnerability/,
+      :confidence => 1,
+      :relative_path => "Gemfile"
+  end
 end
diff --git a/test/tests/rails32.rb b/test/tests/rails32.rb
index 5b7d7f0db7d93e4987a633aa5c1aca2e6a071997..5534a43c66220cd773bb80880956a2fc40507231 100644
--- a/test/tests/rails32.rb
+++ b/test/tests/rails32.rb
@@ -88,6 +88,16 @@ class Rails32Tests < Test::Unit::TestCase
       :file => /Gemfile/
   end
 
+  def test_i18n_xss_CVE_2013_4491
+    assert_warning :type => :warning,
+      :warning_code => 63,
+      :fingerprint => "de0e11056b9f9af7b8570d5354185cd7e17a18cc61d627555fe4adfff00fb447",
+      :warning_type => "Cross Site Scripting",
+      :message => /^Rails\ 3\.2\.9\.rc2\ has\ an\ XSS\ vulnerability/,
+      :confidence => 1,
+      :relative_path => "Gemfile"
+  end
+
   def test_redirect_1
     assert_warning :type => :warning,
       :warning_type => "Redirect",
diff --git a/test/tests/rails4.rb b/test/tests/rails4.rb
index 70207d69d30bad82b983cc9e91f92f798bac1b4d..0a67783e49d1c990abfa5a44d6ad5db40c172c4f 100644
--- a/test/tests/rails4.rb
+++ b/test/tests/rails4.rb
@@ -143,4 +143,60 @@ class Rails4Tests < Test::Unit::TestCase
       :relative_path => "app/controllers/friendly_controller.rb",
       :user_input => s(:call, s(:params), :[], s(:lit, :query))
   end
+
+  def test_i18n_xss_CVE_2013_4491
+    assert_warning :type => :warning,
+      :warning_code => 63,
+      :fingerprint => "de0e11056b9f9af7b8570d5354185cd7e17a18cc61d627555fe4adfff00fb447",
+      :warning_type => "Cross Site Scripting",
+      :message => /^Rails\ 4\.0\.0\ has\ an\ XSS\ vulnerability\ in\ /,
+      :confidence => 1,
+      :relative_path => "Gemfile"
+  end
+
+  def test_denial_of_service_CVE_2013_6414
+    assert_warning :type => :warning,
+      :warning_code => 64,
+      :fingerprint => "a7b00f08e4a18c09388ad017876e3f57d18040ead2816a2091f3301b6f0e5a00",
+      :warning_type => "Denial of Service",
+      :message => /^Rails\ 4\.0\.0\ has\ a\ denial\ of\ service\ vuln/,
+      :confidence => 1,
+      :relative_path => "Gemfile"
+  end
+
+  def test_number_to_currency_CVE_2013_6415
+    assert_warning :type => :template,
+      :warning_code => 66,
+      :fingerprint => "0fb96b5f4b3a4dcdc677d126f492441e2f7b46880563a977b1246b30d3c117a0",
+      :warning_type => "Cross Site Scripting",
+      :line => 9,
+      :message => /^Currency\ value\ in\ number_to_currency\ is\ /,
+      :confidence => 0,
+      :relative_path => "app/views/users/index.html.erb",
+      :user_input => s(:call, s(:call, nil, :params), :[], s(:lit, :currency))
+  end
+
+  def test_simple_format_xss_CVE_2013_6416
+    assert_warning :type => :warning,
+      :warning_code => 67,
+      :fingerprint => "e950ee1043d7f66b7f6ce99c2bf0876bd3ce8cb12818b52565b905cdb6004bad",
+      :warning_type => "Cross Site Scripting",
+      :line => nil,
+      :message => /^Rails\ 4\.0\.0 has\ a\ vulnerability\ in/,
+      :confidence => 1,
+      :relative_path => "Gemfile",
+      :user_input => nil
+  end
+
+  def test_sql_injection_CVE_2013_6417
+    assert_warning :type => :warning,
+      :warning_code => 69,
+      :fingerprint => "e1b66f4311771d714a13be519693c540d7e917511a758827d9b2a0a7f958e40f",
+      :warning_type => "SQL Injection",
+      :line => nil,
+      :message => /^Rails\ 4\.0\.0 contains\ a\ SQL\ injection\ vul/,
+      :confidence => 0,
+      :relative_path => "Gemfile",
+      :user_input => nil
+  end
 end
diff --git a/test/tests/rails4_with_engines.rb b/test/tests/rails4_with_engines.rb
index 7ddb26787c04e026575af6e8ac3bf5243093a91e..efa9c07d48e8a9daed37f05a8b4ef8a0bce8d3ae 100644
--- a/test/tests/rails4_with_engines.rb
+++ b/test/tests/rails4_with_engines.rb
@@ -18,6 +18,16 @@ class Rails4WithEnginesTests < Test::Unit::TestCase
     Rails4WithEngines
   end
 
+  def test_i18n_xss_CVE_2013_4491
+    assert_warning :type => :warning,
+      :warning_code => 63,
+      :fingerprint => "de0e11056b9f9af7b8570d5354185cd7e17a18cc61d627555fe4adfff00fb447",
+      :warning_type => "Cross Site Scripting",
+      :message => /^Rails\ 4\.0\.0\ has\ an\ XSS\ vulnerability\ in\ /,
+      :confidence => 1,
+      :relative_path => "Gemfile"
+  end
+
   def test_redirect_1
     assert_warning :type => :generic,
       :warning_code => 18,