The latest version of PHP in the 4.4.x series has been released today - PHP 4.4.3:

The PHP development team is proud to announce the release of PHP 4.4.3. This release combines small number of bug fixes and resolves a number of security issues.

Some of the updates to this edition include:

• Disallow certain characters in session names.
• Prevent jumps to parent directory via the 2nd parameter of the tempnam() function.
• Fixed cross-site scripting inside the phpinfo() function.
• Upgraded bundled PCRE library to version 6.6

You can download this latest edition here.