diff --git a/lib/mechanize/cookie_jar.rb b/lib/mechanize/cookie_jar.rb
index c8d462d7..c60e279e 100644
--- a/lib/mechanize/cookie_jar.rb
+++ b/lib/mechanize/cookie_jar.rb
@@ -65,7 +65,7 @@ def dump_cookiestxt(io)
   class CookieJar < ::HTTP::CookieJar
     def save(output, *options)
       output.respond_to?(:write) or
-        return open(output, 'w') { |io| save(io, *options) }
+        return ::File.open(output, 'w') { |io| save(io, *options) }
 
       opthash = {
         :format => :yaml,
@@ -119,7 +119,7 @@ def save(output, *options)
 
     def load(input, *options)
       input.respond_to?(:write) or
-        return open(input, 'r') { |io| load(io, *options) }
+        return ::File.open(input, 'r') { |io| load(io, *options) }
 
       opthash = {
         :format => :yaml,
diff --git a/test/test_mechanize_cookie_jar.rb b/test/test_mechanize_cookie_jar.rb
index ce705c14..96f01aef 100644
--- a/test/test_mechanize_cookie_jar.rb
+++ b/test/test_mechanize_cookie_jar.rb
@@ -1,4 +1,5 @@
 require 'mechanize/test_case'
+require 'fileutils'
 
 class TestMechanizeCookieJar < Mechanize::TestCase
 
@@ -500,6 +501,35 @@ def test_save_and_read_cookiestxt_with_session_cookies
     assert_equal(0, @jar.cookies(url).length)
   end
 
+  def test_prevent_command_injection_when_saving
+    url = URI 'http://rubygems.org/'
+    path = '| ruby -rfileutils -e \'FileUtils.touch("vul.txt")\''
+
+    @jar.add(url, Mechanize::Cookie.new(cookie_values))
+
+    in_tmpdir do
+      @jar.save_as(path, :cookiestxt)
+      assert_equal(false, File.exist?('vul.txt'))
+    end
+  end
+
+  def test_prevent_command_injection_when_loading
+    url = URI 'http://rubygems.org/'
+    path = '| ruby -rfileutils -e \'FileUtils.touch("vul.txt")\''
+
+    @jar.add(url, Mechanize::Cookie.new(cookie_values))
+
+    in_tmpdir do
+      @jar.save_as("cookies.txt", :cookiestxt)
+      @jar.clear!
+
+      assert_raises Errno::ENOENT do
+        @jar.load(path, :cookiestxt)
+      end
+      assert_equal(false, File.exist?('vul.txt'))
+    end
+  end
+
   def test_save_and_read_expired_cookies
     url = URI 'http://rubygems.org/'