Refs #14233 - HTML in exception error message will not be replaced.

extension/Classes/Core/Helper/OnArray.php

@@ -138,7 +138,9 @@ class OnArray {
      */
     public static function htmlentitiesOnArray(array $arr) {
         foreach ($arr as $key => $value) {
-            $arr[$key] = htmlentities($arr[$key], ENT_QUOTES);
+
+            // Error message stays the same
+            if ($key !== EXCEPTION_MESSAGE) $arr[$key] = htmlentities($arr[$key], ENT_QUOTES);
         }
 
         return $arr;