WordPress 3.4.2 is now available for download. This update contains several bug fixes as well as some security updates. It is recommended you updated your version of WordPress to 3.4.2 as soon as possible.
“The vulnerabilities included potential privilege escalation and a bug that affects multisite installs with untrusted users. These issues were discovered and fixed by the WordPress security team.”
For a full list of all issues addressed in this update, please look at the 3.4.2 documentation.