How do I check if a sharepoint security update has been superseeded by a new security update

I have been told I must run a security update that appeared on an IA scan.  The update is KB2560890.  I binged this security update and found out it was published in September of 2011.  I looked through the list of updates in programs and features and they are all hotfixes or CUs.  Is there a way to determine if this has been updated since it was released in September of 2011?