Hello amigo,
first run
sudo apt-get update
enter your password when prompted.
When it completes to the prompt again, (at the end of the results), then enter this
apt policy samba
Your results should read -
People should already have this patched version:
Installed: 2:4.3.11+dfsg-0ubuntu0.16.04.7
Candidate: 2:4.3.11+dfsg-0ubuntu0.16.04.7
If so it is patched, it is done.
If not and it has version numbers below those on the lines from Jerry at Installed, and Candidate.
After the next Install Updates is run , Menu>Favourites>Install Updates.
Repeat the above from the beginning and see if the Installed and Candidate are now updated to how Jerry stated.
If yes it is done.
If no repeat the next day after Install updates.