The Windows Forms (aka WinForms) libraries in Microsoft .NET Framework 1.1 SP1, 2.0 SP2, 3.5, 3.5.1, 4, 4.5, 4.5.1, and 4.5.2 allow user-assisted remote attackers to execute arbitrary code via a crafted partial-trust application, aka "Windows Forms Elevation of Privilege Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-048