diff --git a/rubygem-kramdown-2.3.x-restrict-rouge-formatter-namespace-CVE-2021-28834.patch b/rubygem-kramdown-2.3.x-restrict-rouge-formatter-namespace-CVE-2021-28834.patch
new file mode 100644
index 0000000..fd31cb3
--- /dev/null
+++ b/rubygem-kramdown-2.3.x-restrict-rouge-formatter-namespace-CVE-2021-28834.patch
@@ -0,0 +1,70 @@
+From d6a1cbcb2caa2f8a70927f176070d126b2422760 Mon Sep 17 00:00:00 2001
+From: Stan Hu <stanhu@gmail.com>
+Date: Sun, 14 Mar 2021 11:21:00 -0700
+Subject: [PATCH] Restrict Rouge formatters to Rouge::Formatters namespace
+
+ff0218a added support for specifying custom Rouge formatters with the
+constraint that the formatter be in theRouge::Formatters namespace, but
+it did not actually enforce this constraint. For example, this is valid:
+
+```ruby
+Rouge::Formatters.const_get('CSV')
+=> CSV
+```
+
+Adding the `false` parameter to `const_get` prevents this:
+
+```ruby
+Rouge::Formatters.const_get('CSV', false)
+NameError: uninitialized constant Rouge::Formatters::CSV
+```
+---
+ .../converter/syntax_highlighter/rouge.rb      |  2 +-
+ test/test_files.rb                             | 18 +++++++++++-------
+ 2 files changed, 12 insertions(+), 8 deletions(-)
+
+diff --git a/lib/kramdown/converter/syntax_highlighter/rouge.rb b/lib/kramdown/converter/syntax_highlighter/rouge.rb
+index c799526c..ed6a4f83 100644
+--- a/lib/kramdown/converter/syntax_highlighter/rouge.rb
++++ b/lib/kramdown/converter/syntax_highlighter/rouge.rb
+@@ -70,7 +70,7 @@ def self.formatter_class(opts = {})
+       when Class
+         formatter
+       when /\A[[:upper:]][[:alnum:]_]*\z/
+-        ::Rouge::Formatters.const_get(formatter)
++        ::Rouge::Formatters.const_get(formatter, false)
+       else
+         # Available in Rouge 2.0 or later
+         ::Rouge::Formatters::HTMLLegacy
+diff --git a/test/test_files.rb b/test/test_files.rb
+index b446b3bc..7e2ccad3 100644
+--- a/test/test_files.rb
++++ b/test/test_files.rb
+@@ -21,16 +21,20 @@
+   end
+ 
+   # custom formatter for tests
+-  class RougeHTMLFormatters < Kramdown::Converter::SyntaxHighlighter::Rouge.formatter_class
++  module Rouge
++    module Formatters
++      class RougeHTMLFormatters < Kramdown::Converter::SyntaxHighlighter::Rouge.formatter_class
+ 
+-    tag 'rouge_html_formatters'
++        tag 'rouge_html_formatters'
+ 
+-    def stream(tokens, &b)
+-      yield %(<div class="custom-class">)
+-      super
+-      yield %(</div>)
+-    end
++        def stream(tokens, &b)
++          yield %(<div class="custom-class">)
++          super
++          yield %(</div>)
++        end
+ 
++      end
++    end
+   end
+ rescue LoadError, SyntaxError, NameError
+ end
diff --git a/rubygem-kramdown.spec b/rubygem-kramdown.spec
index 7e55a08..2cb4a3c 100644
--- a/rubygem-kramdown.spec
+++ b/rubygem-kramdown.spec
@@ -3,7 +3,7 @@
 
 Name: rubygem-%{gem_name}
 Version: 2.3.0
-Release: 2%{?dist}
+Release: 3%{?dist}
 Summary: Fast, pure-Ruby Markdown-superset converter
 
 License:	MIT
@@ -11,6 +11,9 @@ URL:		http://kramdown.rubyforge.org
 Source0:	https://rubygems.org/gems/%{gem_name}-%{version}.gem
 # https://github.com/gettalong/kramdown/commit/e1beb51af7fe4ecb85dbab7328f47a23c86c7df2
 Patch2:	rubygem-kramdown-2.2.1-rouge-3_26_0-testsuite.patch
+# https://github.com/gettalong/kramdown/pull/708
+# From: https://github.com/gettalong/kramdown/commit/d6a1cbcb2caa2f8a70927f176070d126b2422760
+Patch3:	rubygem-kramdown-2.3.x-restrict-rouge-formatter-namespace-CVE-2021-28834.patch
 BuildRequires:	ruby(release)
 BuildRequires:	rubygems-devel
 BuildRequires:	rubygem(minitest) >= 5
@@ -50,6 +53,7 @@ Documentation for %{name}
 %prep
 %setup -q -n %{gem_name}-%{version}
 %patch2 -p1
+%patch3 -p1
 mv ../%{gem_name}-%{version}.gemspec .
 
 %build
@@ -109,6 +113,9 @@ popd
 %doc	%{gem_docdir}
 
 %changelog
+* Sun Mar 21 2021 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.3.0-3
+- Apply upstream fix for CVE-2021-28834 (rouge formatter namespace restriction)
+
 * Tue Feb 16 2021 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.3.0-2
 - Use recent packaging style