Vulnerabilities in the current version of Microsoft Office could allow remote code execution, accoring to Microsoft. This update resolves several newly-discovered, privately reported and public vulnerabilities.
On vulnerable versions of Office, if a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of the client workstation. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
Microsoft recommends that customers should apply the update immediately.
Download the security patches at http://www.microsoft.com/technet/security/Bulletin/MS06-012.mspx.