kses.php problem

It’s not necessarily the fault of WordPress core. Judging by the line number, a plugin or theme you’re using is sending something that isn’t a string to wp_kses_no_null(). Specifically, something is generating a WP_Error object which isn’t being caught before being sent to wp_kses_no_null().

What is you’re cron doing? One of the places wp_kses_no_null() appears to be used in Core is in sanitizing redirects. Could you be attempting to redirect to a variable that might be an error?

• This reply was modified 6 years, 10 months ago by Jacob Peattie.

Hm, this could be tricky to track down. The normal suggestion is to start disabling plugins one by one until the error stops occurring. In your case you’ll manually need to trigger cron between each plugin.

If the error stops occurring after disabling a plugin, search that plugin’s code for any use of wp_kses_no_null or wp_kses (wp_kses uses wp_kses_no_null internally).

• This reply was modified 6 years, 10 months ago by Jacob Peattie.

I’m also using WP Fastest Cache and suspect that is the source of the issue — I am running this plugin on 10+ sites but only one with the problem. I turned on debugging and the debug log shows entries like this:

[26-Jun-2017 23:24:06 UTC] PHP Notice:  Undefined property: stdClass::$attachment in //wp-content/plugins/wp-fastest-cache/wpFastestCache.php on line 1170
[26-Jun-2017 23:24:06 UTC] PHP Notice:  Array to string conversion in //wp-includes/class-requests.php on line 797
[26-Jun-2017 23:24:06 UTC] PHP Recoverable fatal error:  Object of class WP_Error could not be converted to string in //wp-includes/kses.php on line 1249

I’m going to report this to the plugin developer.