By Qualys have recently released a security advisory for those using OpenSSH clients. In essence using a vulnerable OpenSSH client can expose your private key to a malicious host.
The client has already been patched on most linux / unix based operating systems and administrators of such systems should ensure that they have applied the necessary patches.
So far Apple have not made any mention of this vulnerability in OS X. In order to protect yourself on OS X run the following command in Terminal to add a new line to your SSH configuration:
echo "UseRoaming no" >> ~/.ssh/configFor more information see:
http://www.theregister.co.uk/2016/01/14/openssh_is_wide_open_to_key_theft_thanks_to_roaming_flaw/
https://www.digitalocean.com/community/questions/openssh-client-bug-cve-2016-0777-and-cve-2016-0778