The PHP project has officially released versions 5.4.10 and 5.3.20 if the language:

The PHP development team announces the immediate availability of PHP 5.4.10 and PHP 5.3.20. These releases fix about 15 bugs. Please note that the PHP 5.3 series will enter an end of life cycle and receive only critical fixes as of March 2013. All users of PHP are encouraged to upgrade to PHP 5.4.

Downloads are available here (source) or here for Windows installations. The Changelog has the full list of bugs fixed these two releases. If you're interested in the migration from PHP 5.3 to 5.4 and are wondering what changes you can expect, check out this migration guide with a list of the new features and changes.