As promised, I will keep a close eye on Stefan Esser Month of PHP Bugs project during march 2007. Here are the vulnerabilities exposed on March 1st 2007 :

1. PHP Variable Destructor Deep Recursion Stack Overflow The destruction of deeply nested PHP arrays will exhaust all available stack which leads to remotely triggerable crashes.
2. PHP Executor Deep Recursion Stack Overflow A deep recursion of PHP userland code will exhaust all available stack which leads to a sometimes remotely triggerable crash
3. PHP 4 Userland ZVAL Reference Counter Overflow Vulnerability In PHP 4 userland code is able to overflow the internal 16bit zval reference counter by creating many references to a variable. This leads to an exploitable double dtor condition.

I guess we’ll wait to see what PHP bugs tomorrow brings .