Parameter must be an array or an object that implements Countable

[sanjeevsetu]

Warning: count(): Parameter must be an array or an object that implements Countable in C:\xampp\htdocs\wordpress\wp-includes\post-template.php on line 293

Getting the warning when I use "get_the_excerpt()" in wp_head hook.

​https://prnt.sc/mv1oiy

[jorbin]

I can't reproduce this with a default theme and no plugins enabled using the following test code on php 7.3.2

<?php
add_action( 'wp_head', function(){
        get_the_excerpt();
});

It sounds like a plugin or theme is overriding the $pages global and setting it to the wrong object type.

[l3rady]

We are seeing our logs fill up with this error since moving to PHP 7.2

The error doesn't happen for normal circumstances but happens when we have people probing our site for vulnerabilities where their query string results in the global $pages being returned as null which isn't countable.

An example query string that triggered it for us is the following: index.php?s=%2Fmodule%2Faction%2Fparam1%2F%24%7B%40print%28eval%28%24_POST%5Bc%5D%29%29%7D decoded as index.php?s=/module/action/param1/${@print(eval($_POST[c]))}

It appears that certain conditions can get Wordpress to result in null for $pages and so the code needs to check that $pages are countable.

[SergeyBiryukov]

Hi @sanjeevsetu, welcome to WordPress Trac!

Thanks for the report, we're already tracking this issue in #42814.