PHP versions prior to 5.3.1 suffer from a remote denial of service condition due to server exhaustion from the creation of too many temporary files.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/82834/php530-dos.txt
Source: https://packetstormsecurity.com/files/82834/PHP-5.3.0-Remote-Denial-Of-Service.html