The kex_agree_methods function in libssh2 before 1.5.0 allows remote servers to cause a denial of service (crash) or have other unspecified impact via crafted length values in an SSH_MSG_KEXINIT packet.
http://www.securityfocus.com/bid/73061
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
http://www.libssh2.org/adv_20150311.html
http://www.debian.org/security/2015/dsa-3182
http://lists.fedoraproject.org/pipermail/package-announce/2015-March/153933.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-March/152362.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-March/151943.html