Microsoft recalled a botched security patch for Exchange Server that it had released the day before (Tuesday December 9) in security bulletin MS14-075. The patch was supposed to fix four different vulnerabilities including an Outlook Web App Token Spoofing Vulnerability that could allow a malicious attacker to send email that appears to come from another user. Windows 7 users are being urged to uninstall the broken update because of the problems it can cause, including preventing graphics drivers from being installed and perhaps most seriously the prevention of installing future Windows Updates.”]
Source: https://grahamcluley.com/problems-windows-7-exchange-users-microsoft-warns-buggy-security-patches/