Please make sure you upgrade your PHP version to the latest version as soon as possible as it has a major security flaw which makes websites subject to the following DOS attack.

All you have to do is make PHP interpreter (older than 5.3.5 or 5.2.17) to convert string "2.2250738585072011e-308" to be casted into a numeric type. So if you have a form that accepts numbers which are then cast from strings into numeric values on server side you are probably affected.

Example of this DOS vulnerability

If you have a following form processing script on your site:

<?php
if( $_GET['n'] > 0 ){
    echo "ok";
}else{
    echo "not ok";
}
?>

All you have to do is run the script in the browser with:

script.php?n=2.2250738585072011e-308 

This makes script hang forever using 100% processing capacity on one core. Run a few dozens of those and your server will become unaccessible due to high average load.

Affected systems

From php.net: "The problem is known to only affect x86 32-bit PHP processes, regardless of whether the system hosting PHP is 32-bit or 64-bit.".

My Windows Vista based PHP 5.3 on my laptop is affected as well as my development Debian with PHP 5.3.3. My Mac OSX 5.2 version is not affected. Fortunately all our production servers are pure 64 bit .... but oh man.... that was close!

Stay safe!