PHP Fatal error with defender

  • rickyvbits

    (@rickyvbits)


    2 weeks ago

    Hi all, today we have received a error message from our hosting service provider. Which is related with defender-security. The defender version is 4.9.0, PHP 8.1. We are using WordPress for this site.

    2026/04/28 01:40:54 [error] 11824#11824: *119734 FastCGI sent in stderr: “PHP message: PHP Warning: Undefined array key “verify_blocked_user” in /www/XXXXXXX_267/public/wp-content/plugins/defender-security/src/controller/class-firewall.php on line 584PHP message: PHP Warning: Undefined array key “verify_blocked_user” in /www/XXXXXXX_267/public/wp-content/plugins/defender-security/src/controller/class-firewall.php on line 585PHP message: PHP Fatal error: Uncaught TypeError: WP_Defender\Controller::check_route(): Argument #1 ($route) must be of type string, null given, called in /www/XXXXXXX_267/public/wp-content/plugins/defender-security/src/controller/class-firewall.php on line 585 and defined in /www/XXXXXXX_267/public/wp-content/plugins/defender-security/src/class-controller.php:195

    We have staging and production environment, that error is happened on production only. We have compared with staging and production’s system environment, all the plug-in and PHP version are the same.

    I have reference the threads before which is enable the “OPcache_save_comments” can fix it. But I have other site using the same PHP version but no error.

    Any hints for trouble shoot this error? Thank you.

Viewing 3 replies - 1 through 3 (of 3 total)
  • Fida – WPMU DEV Support

    (@fidawpmudev)

    1 week, 6 days ago

    Hello @rickyvbits ,

    I hope you are doing well.

    Your site is currently using Defender version 4.9.0, which is quite outdated. Please update Defender to the latest available version, 5.11.0, and then check whether this resolves the issue.

    If the issue continues after updating, please enable opcache.save_comments on your hosting environment and test again to see if that helps.

    But I have other site using the same PHP version but no error.

    Could you please confirm whether those sites are hosted on the same server, and whether opcache.save_comments is also disabled there?

    Please also note that PHP 8.1 reached its official End of Life (EOL) on December 31, 2025. Since then, PHP 8.1 no longer receives security patches, bug fixes, or official support from the PHP development team. This may expose applications to unresolved vulnerabilities and compatibility risks. I strongly recommend upgrading to PHP 8.2 or higher at your earliest convenience.

    Kind Regards,
    Fida Al Hasan

    Thread Starter rickyvbits

    (@rickyvbits)

    4 days, 17 hours ago

    Hello @fidawpmudev ,

    Thank you for your response. We will discuss to update the Defender version. I have another side running on same server with same PHP8.1. Defender version is older than 4.9.0 but we haven’t receive any PHP error notice. By the way. We will try to update the defender version first. Thank you for the support.

    Best Regards,
    Ricky

    Plugin Support Nebu John – WPMU DEV Support

    (@wpmudevsupport14)

    4 days, 13 hours ago

    Hi @rickyvbits,

    I hope updating Defender helps to resolve the issue.

    Could you confirm if the other site is running on the same server? Also, could you verify if opcache.save_comments is disabled on them as well?

    Looking forward to hearing back from you.

    Best Regards,
    Nebu John

Viewing 3 replies - 1 through 3 (of 3 total)

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