The PHP group has announced the release of the latest version in the 5.2.x series for PHP - 5.2.12:

The PHP development team would like to announce the immediate availability of PHP 5.2.12. This release focuses on improving the stability of the PHP 5.2.x branch with over 60 bug fixes, some of which are security related. All users of PHP 5.2 are encouraged to upgrade to this release.

Bugs/security issues corrected in the release include problems with tempnam(), posix_mkfifo(), the addition of a max_file_uploads directive, protection for session corruption and validtion for htmlspecialchars()

As always, you can download the source from the PHP.net downloads page and the Windows binaries from windows.php.net.