Has anyone else seen this error under Joomla and CiviCRM 5.10.4 when viewing a contact via the front end?

Warning: hash_equals(): Expected user_string to be a string, null given in /.../administrator/components/com_civicrm/civicrm/CRM/Contact/BAO/Contact/Utils.php on line 232

  • Are you viewing the contact via a link that has "cs=" in the url?
    – Demerit
    Mar 5, 2019 at 15:51
  • Not that I am aware. $inputCheck is null when validChecksum is called, CRM_Utils_Request::retrieve('cs', 'String', $form, FALSE) returns a null value. Mar 6, 2019 at 13:05
  • I'm having the same issue after upgrading to CiviCRM 5.13.12 May 7, 2019 at 18:58

2 Answers 2


I am also receiving this error but on Wordpress 5.2.1 and civiCRM 5.13.4. I have not found a solution to this either.


I had this problem in Wordpress 5.2.1 and CiviCRM 5.13.4 too. Changing line 232 to the following:

if (!hash_equals((string)$check, (string)$inputCheck)) {

in the file: civicrm\civicrm\CRM\Contact\BAO\Contact\Utils.php fixed the problem.

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