There are security patches for earlier versions of Open Office.

OpenOffice has released two patches to repair older versions of its open-source office productivity suite.

The two vulnerabilities do not affect OpenOffice.org's latest 3.0 version, released earlier this month. Software versions prior to version 2.4.2 are affected.
The product is now at version 3.0, which you can get here:

http://download.openoffice.org/

That is the latest stable version. If you go elsewhere, be careful as there is also a beta 2 out there.