Today Drupal 7.3 and Drupal 7.4 has been released.
In version 7.3, only include security fixes that are discovered by numerous people, including Sascha Grossenbacher, Khaled Alhourani, and Ben Ford. Version that affected are Drupal 7.0, 7.1 and 7.2, so you should upgrade your Drupal sites to newer version immediately.
Besides releasing version 7.3, version 7.4 has also been released at the same time, and this is the fourth maintenance release of the Drupal 7 series. In version 7.4 there is no security improvement, and only contains bugfixes to the core.
You can read the Drupal 7.4 release here, and download the Drupal 7.4 here.