Recently released security update (KB3013455) has caused ‘Courier New’ font corruption in Windows Server 2003 and 2008 OS. This security update was meant for Windows kernel mode driver and was supposed to resolve one publicly disclosed vulnerability and five privately reported vulnerabilities in Microsoft Windows OS.
The most severely affected by these vulnerabilities can allow remote code execution, if an attacker convinces a user to open a specially crafted document or visit a non-trusted website that contains embedded TrueType fonts.
Known issues with this security update
After installing this security update, you may notice some text quality degradation in certain cases. Some text quality degradation actually makes it unreadable. According to Microsoft, this problem only occurs on systems that are running Windows Vista SP2 or Windows Server 2003 SP2. However, we do confirm that, it has also affected Windows Server 2008 R2 OS.
As of now, removing the update is the only way to fix “Font Quality Degradation” problem. Until now, there is no patch released to fix this issue. As an alternative, you can also change the default font type to some other font.