The diffie_hellman_sha256 function in kex.c in libssh2 before 1.7.0 improperly truncates secrets to 128 or 256 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://lists.fedoraproject.org/pipermail/package-announce/2016-February/177980.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-March/178573.html
http://lists.opensuse.org/opensuse-updates/2016-03/msg00008.html
https://kc.mcafee.com/corporate/index?page=content&id=SB10156
https://security.gentoo.org/glsa/201606-12
http://www.debian.org/security/2016/dsa-3487
http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html