Severity Rating: Important - Revision Note: V2.0 (April 29, 2009): Added an entry to the section, Frequently Asked Questions (FAQ) Related to This Security Update to communicate the rerelease of the Norwegian-language update for Microsoft Windows 2000 Service Pack 4 (KB952004). Customers who require the Norwegian-language update need to download and install the rereleased update. No other updates or locales are affected by this rerelease.Summary: This security update resolves four publicly disclosed vulnerabilities in Microsoft Windows. The vulnerabilities could allow elevation of privilege if an attacker is allowed to log on to the system and then run a specially crafted application. The attacker must be able to run code on the local machine in order to exploit this vulnerability. An attacker who successfully exploited any of these vulnerabilities could take complete control over the affected system.

Read more at: http://www.microsoft.com/technet/security/bulletin/MS09-012.mspx?pubDate=2009-04-29