The TCP stack in 4.3BSD Net/2, as used in FreeBSD 5.4, NetBSD possibly 2.0, and OpenBSD possibly 3.6, does not properly implement the session timer, which allows remote attackers to cause a denial of service (resource consumption) via crafted packets.

The OpenSSH server, as used in Fedora and Red Hat Enterprise Linux 7 and when running in a Kerberos environment, allows remote authenticated users to log in as another user when they are listed in the .k5users file of that user, which might bypass intended authentication requirements that would force a local login.

OpenSMTPD before 5.3.2 does not properly handle SSL sessions, which allows remote attackers to cause a denial of service (connection blocking) by keeping a connection open.

The verify_host_key function in sshconnect.c in the client in OpenSSH 6.6 and earlier allows remote servers to trigger the skipping of SSHFP DNS RR checking by presenting an unacceptable HostCertificate.

sshd in OpenSSH before 6.6 does not properly support wildcards on AcceptEnv lines in sshd_config, which allows remote attackers to bypass intended environment restrictions by using a substring located before a wildcard character.

ssh-keysign.c in ssh-keysign in OpenSSH before 5.8p2 on certain platforms executes ssh-rand-helper with unintended open file descriptors, which allows local users to obtain sensitive key information via the ptrace system call.

The hash_buffer function in schnorr.c in OpenSSH through 6.4, when Makefile.inc is modified to enable the J-PAKE protocol, does not initialize certain data structures, which might allow remote attackers to cause a denial of service (memory corruption) or have unspecified other impact via vectors that trigger an error condition.

The mm_newkeys_from_blob function in monitor_wrap.c in sshd in OpenSSH 6.2 and 6.3, when an AES-GCM cipher is used, does not properly initialize memory for a MAC context data structure, which allows remote authenticated users to bypass intended ForceCommand and login-shell restrictions via packet data that provides a crafted callback address.

The default configuration of OpenSSH through 6.1 enforces a fixed time limit between establishing a TCP connection and completing a login, which makes it easier for remote attackers to cause a denial of service (connection-slot exhaustion) by periodically making many new TCP connections.

The ssh_gssapi_parse_ename function in gss-serv.c in OpenSSH 5.8 and earlier, when gssapi-with-mic authentication is enabled, allows remote authenticated users to cause a denial of service (memory consumption) via a large value in a certain length field. NOTE: there may be limited scenarios in which this issue is relevant.