“Thomas Mackenzie alerted us to a problem where logged in users can peek at trashed posts belonging to other authors. If you have untrusted users signed up on your blog and sensitive posts in the trash, you should upgrade to 2.9.2. As always, you can visit the Tools->Upgrade menu to upgrade.”
Here the question is should you upgrade to this latest version? The answer is you can leave it if you do not have multiple authors in your blog but if you are using WP version prior to 2.9.1 then you may go ahead and update it to 2.9.2.
Download WordPress 2.9.2 here.