CVE-2009-4418

The unserialize function in PHP 5.3.0 and earlier allows context-dependent attackers to cause a denial of service (resource consumption) via a deeply nested serialized variable, as demonstrated by a string beginning with a:1: followed by many {a:1: sequences.

Date published : 2009-12-24

http://www.suspekt.org/2009/11/28/shocking-news-in-php-exploitation/

http://www.suspekt.org/downloads/POC2009-ShockingNewsInPHPExploitation.pdf