Google’s disclosure of a Windows 8.1 vulnerability which could allow normal users to gain administrative-level access was reported to Microsoft on September 30. In fact, Microsoft responded to the issue saying: “We are working to release a security update to address an Elevation of Privilege issue. It is important to note that for a would-be attacker to potentially exploit a system, they would first need to have valid logon credentials and be able to log on locally to a targeted machine. We encourage customers to keep their anti-virus software up to date, install all available Security Updates and enable the firewall on their computer.”
Read more here – https://code.google.com/p/google-security-research/issues/detail?id=118&can=1