With an Internet connected standalone ESXi host you can use the well known esxcli method to patch the host directly from the VMware Online Depot:
Enable SSH access on your host, log in to it (e.g. using putty) and run the following commands:
# open firewall for outgoing http requests:
esxcli network firewall ruleset set -e true -r httpClient
# View available ESXi Image Profiles
esxcli software sources profile list -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml
# Update using the ESXi Imageprofile from the VMware Online depot
esxcli software profile update -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml -p "type the name of the imageprofile here"
# Reboot your host
reboot