MS13-033  Vulnerability in Windows Client/Server Run-time Subsystem (CSRSS) Could Allow Elevation of Privilege

2013-04-09 This security update resolves a privately reported vulnerability in all supported editions of Windows XP, Windows Vista, Windows Server 2003, and Windows Server 2008. The vulnerability could allow elevation of privilege if an attacker logs on to a system and runs a specially crafted application. An attacker must have valid logon credentials and be able to log on locally to exploit this vulnerability.
Vulnerabilities addressed in this bulletin:

CSRSS Memory Corruption Vulnerability

An elevation of privilege vulnerability exists when the Windows CSRSS improperly handles objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in the context of the local system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
CVE-2013-1295

Bulletin details at Microsoft.com