First identify your image.
$ docker ps --format ": "3d2fb2ab2ca5: jenkins-docker jenkins-docker_1
Then login into the image as root.
$ docker container exec -u 0 -it jenkins-docker_1 /bin/bash
Now you are inside the container, download the
jenkins.war file from the official site like.
# wget http://updates.jenkins-ci.org/download/war/2.176.1/jenkins.war
Replace the version with the one that fits to you.
The next step is to move that file and replace the oldest one.
# mv ./jenkins.war /usr/share/jenkins/
Then change permissions.
# chown jenkins:jenkins /usr/share/jenkins/jenkins.war
The last step is to logout from the container and restart it.
$ docker restart jenkins-docker_1
You can verify that update was successful by access to you Jenkins url.