Patch 20.4.0.40. Security problem?

Dear Forum,

I have a security concern regarding the installation of this Patch . I have run the LiveUpdate and this Patch was installed. After applying this patch (button in the LiveUpdate windows: "Apply now") NIS program was closed for some seconds and then started again.

All this time I was connected to the internet, since NIS is using its own Firewall I guess the PC was not protected from intrusion from the network? 

Please correct me if I am wrong.