The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c.
https://support.apple.com/HT205375
https://security.netapp.com/advisory/ntap-20180201-0002/
https://security.gentoo.org/glsa/201512-04
https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
https://github.com/openssh/openssh-portable/commit/d4697fe9a28dab7255c60433e4dd23cf7fce8a8b
https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
http://www.securityfocus.com/bid/76317
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
http://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
http://www.openwall.com/lists/oss-security/2015/08/22/1
http://www.openssh.com/txt/release-7.0
http://seclists.org/fulldisclosure/2015/Aug/54
http://rhn.redhat.com/errata/RHSA-2016-0741.html
http://lists.opensuse.org/opensuse-security-announce/2015-09/msg00017.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-August/165170.html
http://lists.apple.com/archives/security-announce/2015/Oct/msg00005.html