Ticket #28162: 28162.patch

src/wp-includes/formatting.php

@@ -410 +410 @@
  * @return bool True if $str fits a UTF-8 model, false otherwise.
  */
 function seems_utf8($str) {
+        mbstring_binary_safe_encoding();
         $length = strlen($str);
+        reset_mbstring_encoding();
         for ($i=0; $i < $length; $i++) {
                 $c = ord($str[$i]);
                 if ($c < 0x80) $n = 0; # 0bbbbbbb