Initially after upgrading everything was working great until I tried to SSH into an older legacy linux server and was greeted with this lovely message:
sign_and_send_pubkey: no mutual signature supported firstname.lastname@example.org: Permission denied (publickey).
The reason for this issue is that MacOS 13 ships with OpenSSH_9.0p1 which has disabled RSA signatures on SHA-1 hash algorithms. If upgrading OpenSSH on the server and/or regenerating your SSH key isn’t an option you can workaround this issue by adding the following to your
Host * HostkeyAlgorithms +ssh-rsa PubkeyAcceptedAlgorithms +ssh-rsa
If you don’t want to add this across the board you can also pass an SSH option when connecting via SSH as follows:
ssh -o 'PubkeyAcceptedKeyTypes +ssh-rsa' -i ~/.ssh/yourkey email@example.com