Citings? I don't see anything about Vars corrupting data specifically. In perldoc CGI:

"Note that you must use ->upload or ->param to get the file-handle to pass into uploadInfo as internally this is represented as a File::Temp object (which is what will be returned by ->upload or ->param). When using ->Vars you will get the literal filename rather than the File::Temp object, which will not return anything when passed to uploadInfo. So don't use ->Vars."

"If you are using a machine that recognizes "text" and "binary" data modes, be sure to understand when and how to use them (see the Camel book). Otherwise you may find that binary files are corrupted during file uploads."

When making blanket statements like "CGI->Vars corrupts data", please source it with authoritative material (where available), or at least explain some detail of the problem.