An information leak flaw was found in the way the OpenSSH client roaming feature was implemented. A malicious server could potentially use this flaw to leak portions of memory (possibly including private SSH keys) of a successfully authenticated OpenSSH client (CVE-2016-0777).
A buffer overflow flaw was found in the way the OpenSSH client roaming feature was implemented. A malicious server could potentially use this flaw to execute arbitrary code on a successfully authenticated OpenSSH client if that client used certain non-default configuration options (CVE-2016-0778).
The issue only affects OpenSSH clients making use of the ProxyCommand feature. This update disables the roaming feature completely.