update-github-rsa-ssh-host-key.md

Update GitHub RSA SSH Host Key

Category: Git

On 23 March 2023, GitHub updated their RSA SSH host key after the private key was briefly exposed in a public GitHub repository.

An SSH key which has not been updated will display a message similar to the following when trying to push to GitHub:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
SHA256:uNiVztksCsDhcc0u9e8BujQXVUpKZIDTMczCvj3tD2s.

Remove the GitHub SSH key from your known hosts:

ssh-keygen -R github.com

To update the key, either push to your remote repository on GitHub where you will be asked to add the new key to known hosts, or run the following command:

curl -L https://api.github.com/meta | jq -r '.ssh_keys | .[]' | sed -e 's/^/github.com /' >> ~/.ssh/known_hosts