1 files changed, 3 insertions, 2 deletions
diff --git a/actionmailer/lib/action_mailer/vendor/tmail/quoting.rb b/actionmailer/lib/action_mailer/vendor/tmail/quoting.rb
index 626e88238f..1ff00d9299 100644
--- a/actionmailer/lib/action_mailer/vendor/tmail/quoting.rb
+++ b/actionmailer/lib/action_mailer/vendor/tmail/quoting.rb
@@ -9,7 +9,8 @@ begin
       end
 
       def unquoted_body(to_charset = 'utf-8')
-        Unquoter.unquote_and_convert_to(quoted_body, to_charset, header["content-type"]["charset"])
+        from_charset = header['content-type']['charset'] rescue 'us-ascii'
+        Unquoter.unquote_and_convert_to(quoted_body, to_charset, from_charset)
       end
 
       def body(to_charset = 'utf-8', &block)
@@ -97,4 +98,4 @@ rescue LoadError => e
       end
     end
   end
-end
-\ No newline at end of file
+end