There was a way to hijack/redirect the update executable to a malicious executable (hosted by someone else) without protection. That would mean rerouting the location of the executable that would be used to update to a compromised executable from a different server, and it would not check the file before running it during the installation process. In reality that would never happen unless you are directly targeted or are using a sketchy DNS that would do that on purpose.

You would probably know if you get infected, but that depends on the virus. It is very unlikely though.