libssh before 0.7.3 improperly truncates ephemeral secrets generated for the (1) diffie-hellman-group1 and (2) diffie-hellman-group14 key exchange methods to 128 bits, which makes it easier for man-in-the-middle attackers to decrypt or intercept SSH sessions via unspecified vectors, aka a bits/bytes confusion bug. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-0739
