VsaVb7rt.dll in Microsoft .NET Framework 2.0 SP2 and 3.5.1 does not implement the ASLR protection mechanism, which makes it easier for remote attackers to execute arbitrary code via a crafted web site, as exploited in the wild in February 2014, aka "VSAVB7RT ASLR Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-009
http://www.securitytracker.com/id/1029745
http://www.securityfocus.com/bid/65418