[wp-hackers] canary mismatch on efree() - heap overflow detected

[jeff at jrm.cc]

Quoting Knut-Olav Hoven <hovenko at linpro.no>:
> I get the following in my Apache error log.
>
> Aug  2 16:28:20 beta suhosin[49368]: ALERT - canary mismatch on   
> efree() - heap
> overflow detected (attacker '127.0.0.1',
> file '/some/dir/wordpress/wp-includes/kses.php', line 518)

I got this same error and I think it's a problem with op caching kses.

Try modifying the kses.php file so that the opcache has to be redone  
-- should clear the problem. Not sure if that will keep it from doing  
it again though, but mine hasn't reoccured.

Jeff