6.1.7 and 6.2.6 Updates Causing Critical Errors

  • Unknown's avatar
    wstdevelopment · Member ·

    Today we had around 20+ sites go down sporadically across multiple servers and hosting providers. All of the sites were on 6.1.7 or 6.2.6 and had the same errors:
    PHP Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function “_wp_footnotes_kses_init” not found or invalid function name in /wp-includes/class-wp-hook.php:308

    After verifying checksums on core we found that the wp-includes/default-filters.php file did not match and we had to re-download core on all the sites to get rid of the critical error. I imagine this will be happening for us most of the day. We checked server and security logs and didn’t find anything correlated to the issue and believe it may be something to do with the update methods. Not sure but some insight here would be helpful.

  • rwye1 · Staff ·

    Hi there,

    Could you please share which sites this is impacting? I checked your WordPress.com account, but I wasn’t able to find any sites hosted on WordPress.com.

    If your sites are currently hosted by a different provider, I’d recommend posting on the WordPress.org support forums here: https://wordpress.org/support/forums/

    I can see a WordPress core ticket for the issue reported here: https://core.trac.wordpress.org/ticket/61489, so the issue will continue to be worked on from there as well.

  • Unknown's avatar
    miacmk · Member ·

    I’m also having the same issue, trying to figure out how to fix it. You have any solutions?

  • Unknown's avatar
    zerge · Member ·

    The fix is here:

    After verifying checksums on core we found that the wp-includes/default-filters.php file did not match and we had to re-download core on all the sites to get rid of the critical error.

  • rwye1 · Staff ·

    Hi @miacmk,

    If you are experiencing any issues with a WordPress.com hosted site, could you please create a separate forum thread here: https://wordpress.com/forums/. We’ll be happy to take a look for you.

    Sites on WordPress.com currently use version 6.5.5, so it looks like this issue is impacting self-hosted WordPress.org sites on older versions. If your site is with a separate host, we recommend contacting your hosting provider, or posting in the existing trac ticket here: https://core.trac.wordpress.org/ticket/61489.

    Please keep in mind that the most recent release is the most recommended, maintained, and safe version to use.

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