PHP 5.3.9 along with any older versions for which the hash collision DoS patch was backported, are affected, Eiram said.

A similar exploit for the PHP version would not be hard to produce. “All users are strongly encouraged to upgrade to PHP 5.3.9,” the platform’s developers said.

The PHP development team addressed CVE-2011-4885 in PHP 5.3.9, which was released on Jan. 10.