An update for PHP was released late in the day on January 5 that addresses a floating point bug in the previous versions.  While not a security risk, the bug could cause a system running PHP to exhibit a denial of service condition due to an exhaustion of system resources when attempting to calculate the correct floating point value.

This condition could be experienced on both Windows and Linux systems running PHP.  Additional details can be found at the following URL

http://www.networkworld.com/news/2011/010511-php-floating-point-bug-fix.html

Update versions are available from  http://www.php.net/downloads.php#v5