diff --git a/app/models/mail_handler.rb b/app/models/mail_handler.rb
index 2aaa8bbf0..deb27e22a 100755
--- a/app/models/mail_handler.rb
+++ b/app/models/mail_handler.rb
@@ -44,7 +44,7 @@ class MailHandler < ActionMailer::Base
     options[:no_permission_check] = (options[:no_permission_check].to_s == '1')
 
     ActiveSupport::Notifications.instrument("receive.action_mailer") do |payload|
-      mail = Mail.new(raw_mail.b)
+      mail = Mail.new(Mail::Utilities.binary_unsafe_to_crlf(raw_mail.b))
       set_payload_for_mail(payload, mail)
       new.receive(mail, options)
     end
diff --git a/test/fixtures/mail_handler/thunderbird_with_utf8_body_and_lf_lineterminator_and_attachment.eml b/test/fixtures/mail_handler/thunderbird_with_utf8_body_and_lf_lineterminator_and_attachment.eml
new file mode 100644
index 000000000..949eb2dd0
--- /dev/null
+++ b/test/fixtures/mail_handler/thunderbird_with_utf8_body_and_lf_lineterminator_and_attachment.eml
@@ -0,0 +1,32 @@
+To: redmine@somenet.foo
+From: John Smith <JSmith@somenet.foo>
+Subject: =?UTF-8?B?44OG44K544OI44Oh44O844Or?=
+Message-ID: <cef02a8b-5359-58f3-6403-bc2bb3c93c43@somenet.foo>
+Date: Mon, 10 Jun 2019 13:39:21 +0900
+User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0)
+ Gecko/20100101 Thunderbird/60.7.0
+MIME-Version: 1.0
+Content-Type: multipart/mixed;
+ boundary="------------6FE4347B4294DF3B19BB9898"
+Content-Language: en-US
+
+This is a multi-part message in MIME format.
+--------------6FE4347B4294DF3B19BB9898
+Content-Type: text/plain; charset=utf-8; format=flowed
+Content-Transfer-Encoding: 8bit
+
+Ｔｏ：redmine
+
+　テストメールを送信します。
+
+--------------6FE4347B4294DF3B19BB9898
+Content-Type: application/zip; x-mac-type="0"; x-mac-creator="0";
+ name="test.zip"
+Content-Transfer-Encoding: base64
+Content-Disposition: attachment;
+ filename="test.zip"
+
+UEsDBBQAAAAAAE8/xU4Mfn/YBAAAAAQAAAAIAAAAdGVzdC50eHR0ZXN0UEsBAhQAFAAAAAAA
+Tz/FTgx+f9gEAAAABAAAAAgAAAAAAAAAAQAgAAAAAAAAAHRlc3QudHh0UEsFBgAAAAABAAEA
+NgAAACoAAAAAAA==
+--------------6FE4347B4294DF3B19BB9898--
diff --git a/test/unit/mail_handler_test.rb b/test/unit/mail_handler_test.rb
index ed064f6f7..bb3cb58d3 100644
--- a/test/unit/mail_handler_test.rb
+++ b/test/unit/mail_handler_test.rb
@@ -415,6 +415,26 @@ class MailHandlerTest < ActiveSupport::TestCase
     assert mail.subject.include?('New ticket on a given project')
   end
 
+  def test_add_issue_with_utf8_body_and_lf_line_terminator_and_attachment
+    assert_difference 'Issue.count' do
+      issue = submit_email(
+        'thunderbird_with_utf8_body_and_lf_lineterminator_and_attachment.eml',
+        :issue => {:project => 'ecookbook'}
+      ) do |email|
+        # Ensure that line terminators are LF
+        email.gsub!(/\r\n?/, "\n")
+      end
+
+      assert issue.is_a?(Issue)
+      assert_equal 'テストメール', issue.subject
+      assert_equal "Ｔｏ：redmine\r\n\r\n　テストメールを送信します。", issue.description
+
+      assert_equal 1, issue.attachments.size
+      assert_equal 'test.zip', issue.attachments.first.filename
+      assert_equal 118, issue.attachments.first.filesize
+    end
+  end
+
   def test_created_user_should_be_added_to_groups
     group1 = Group.generate!
     group2 = Group.generate!