Why do you believe that PuTTY is susceptible to OpenSSH bugs?
PuTTY and WinSCP do not use any OpenSSH code.
I was not aware they don't use OpenSSH; so now I'm really confused. Due to the discovery of the vulnerability, our network guys "shut this down" (whatever that means), and all transfers failed after that point. They rolled the change back and the transfers are working again. I am going to reach out to them and see what exactly it is they are blocking at the firewall to make sure they aren't blocking something they should be letting through. If WinSCP isn't using OpenSSH and whatever they are changing is causing it to fail, they must be blocking something else in addition to OpenSSH. Thanks for the prompt reply.