Stolen credentials from SSH clients via ssh-agent program, allowing other local users to access remote accounts belonging to the ssh-agent user.

A race condition in the authentication agent mechanism of sshd 1.2.17 allows an attacker to steal another user's credentials.

SSH 1.2.25 on HP-UX allows access to new user accounts.

In some instances of SSH 1.2.27 and 2.0.11 on Linux systems, SSH will allow users with expired accounts to login.

The SSH authentication agent follows symlinks via a UNIX domain socket.

SSH server (sshd2) before 2.0.12 does not properly record login attempts if the connection is closed before the maximum number of tries, allowing a remote attacker to guess the password without showing up in the audit logs.

SSH 1.2.25, 1.2.23, and other versions, when used in in CBC (Cipher Block Chaining) or CFB (Cipher Feedback 64 bits) modes, allows remote attackers to insert arbitrary data into an existing stream between an SSH client and server by using a known plaintext attack and computing a valid CRC-32 checksum for the packet, aka the "SSH insertion attack."

SSH 2.0.11 and earlier allows local users to request remote forwarding from privileged ports without being root.

ssh 2.0.12, and possibly other versions, allows valid user names to attempt to enter the correct password multiple times, but only prompts an invalid user name for a password once, which allows remote attackers to determine user account names on the server.

The SSH protocol server sshd allows local users without shell access to redirect a TCP connection through a service that uses the standard system password database for authentication, such as POP or FTP.

The default configuration of SSH allows X forwarding, which could allow a remote attacker to control a client's X sessions via a malicious xauth program.

SSH 1.2.27 with Kerberos authentication support stores Kerberos tickets in a file which is created in the current directory of the user who is logging in, which could allow remote attackers to sniff the ticket cache if the home directory is installed on NFS.

Directory traversal vulnerability in scp in sshd 1.2.xx allows a remote malicious scp server to overwrite arbitrary files via a .. (dot dot) attack.

CORE SDI SSH1 CRC-32 compensation attack detector allows remote attackers to execute arbitrary commands on an SSH server or client via an integer overflow.

ssh-keygen in ssh 1.2.27 - 1.2.30 with Secure-RPC can allow local attackers to recover a SUN-DES-1 magic phrase generated by another user, which the attacker can use to decrypt that user's private key file.

Implementations of SSH version 1.5, including (1) OpenSSH up to version 2.3.0, (2) AppGate, and (3) ssh-1 up to version 1.2.31, in certain configurations, allow a remote attacker to decrypt and/or alter traffic via a "Bleichenbacher attack" on PKCS#1 version 1.5.

SSH Communications Security sshd 2.4 for Windows allows remote attackers to create a denial of service via a large number of simultaneous connections.

SSH daemon version 1 (aka SSHD-1 or SSH-1) 1.2.30 and earlier does not log repeated login attempts, which could allow remote attackers to compromise accounts without detection via a brute force attack.

SSH Secure Shell 3.0.0 on Unix systems does not properly perform password authentication to the sshd2 daemon, which allows local users to gain access to accounts with short password fields, such as locked accounts that use "NP" in the password field.

The SSH protocols 1 and 2 (aka SSH-2) as implemented in OpenSSH and other packages have various weaknesses which can allow a remote attacker to obtain the following information via sniffing: (1) password lengths or ranges of lengths, which simplifies brute force password guessing, (2) whether RSA or DSA authentication is being used, (3) the number of authorized_keys in RSA authentication, or (4) the lengths of shell commands.

The RC4 stream cipher as used by SSH1 allows remote attackers to modify messages without detection by XORing the original message's cyclic redundancy check (CRC) with the CRC of a mask consisting of all the bits of the original message that were modified.

The IDEA cipher as implemented by SSH1 does not protect the final block of a message against modification, which allows remote attackers to modify the block without detection by changing its cyclic redundancy check (CRC) to match the modifications to the message.

The SSH-1 protocol allows remote servers to conduct man-in-the-middle attacks and replay a client challenge response to a target server by creating a Session ID that matches the Session ID of the target, but which uses a public key pair that is weaker than the target's public key, which allows the attacker to compute the corresponding private key and use the target's Session ID with the compromised key pair to masquerade as the target.

SSH before 2.0 disables host key checking when connecting to the localhost, which allows remote attackers to silently redirect connections to the localhost by poisoning the client's DNS cache.

SSH before 2.0, when using RC4 and password authentication, allows remote attackers to replay messages until a new server key (VK) is generated.

SSH before 2.0, with RC4 encryption and the "disallow NULL passwords" option enabled, makes it easier for remote attackers to guess portions of user passwords by replaying user sessions with certain modifications, which trigger different messages depending on whether the guess is correct or not.

SSH Secure Shell for Servers and SSH Secure Shell for Workstations 2.0.13 through 3.2.1, when running without a PTY, does not call setsid to remove the child process from the process group of the parent process, which allows attackers to gain certain privileges.

Buffer overflow in the URL catcher feature for SSH Secure Shell for Workstations client 3.1 to 3.2.0 allows remote attackers to execute arbitrary code via a long URL.

SSH Secure Shell for Servers 3.0.0 to 3.1.1 allows remote attackers to override the AllowedAuthentications configuration and use less secure authentication schemes (e.g. password) than configured for the server.

SSH 1 through 3, and possibly other versions, allows local users to bypass restricted shells such as rbash or rksh by uploading a script to a world-writeable directory, then executing that script to gain normal shell access.

SSH Secure Shell before 3.2.9 allows remote attackers to cause a denial of service via malformed BER/DER packets.

Race condition in SSH Tectia Server 4.0.3 and 4.0.4 for Unix, when the password change plugin (ssh-passwd-plugin) is enabled, allows local users to obtain the server's private key.

SSH Tectia Server 4.3.1 and earlier, and SSH Secure Shell for Windows Servers, uses insecure permissions when generating the Secure Shell host identification key, which allows local users to access the key and spoof the server.

SSH Tectia Server 5.0.0 (A, F, and T), when allowing host-based authentication only, allows users to log in with the wrong credentials.

The random number generator in the Crypto application before 2.0.2.2, and SSH before 2.0.5, as used in the Erlang/OTP ssh library before R14B03, uses predictable seeds based on the current time, which makes it easier for remote attackers to guess DSA host and SSH session keys.

The SSH USERAUTH CHANGE REQUEST feature in SSH Tectia Server 6.0.4 through 6.0.20, 6.1.0 through 6.1.12, 6.2.0 through 6.2.5, and 6.3.0 through 6.3.2 on UNIX and Linux, when old-style password authentication is enabled, allows remote attackers to bypass authentication via a crafted session involving entry of blank passwords, as demonstrated by a root login session from a modified OpenSSH client with an added input_userauth_passwd_changereq call in sshconnect2.c.

SSH Tectia Client and Server before 6.4.19 on Windows have weak key generation. ConnectSecure on Windows is affected.

SSH Tectia Client and Server before 6.4.19 on Windows allow local privilege escalation. ConnectSecure on Windows is affected.

SSH Tectia Client and Server before 6.4.19 on Windows allow local privilege escalation in nonstandard conditions. ConnectSecure on Windows is affected.

The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from the extension negotiation message), and a client and server may consequently end up with a connection for which some security features have been downgraded or disabled, aka a Terrapin attack. This occurs because the SSH Binary Packet Protocol (BPP), implemented by these extensions, mishandles the handshake phase and mishandles use of sequence numbers. For example, there is an effective attack against SSH's use of ChaCha20-Poly1305 (and CBC with Encrypt-then-MAC). The bypass occurs in chacha20-poly1305@openssh.com and (if CBC is used) the -etm@openssh.com MAC algorithms. This also affects Maverick Synergy Java SSH API before 3.1.0-SNAPSHOT, Dropbear through 2022.83, Ssh before 5.1.1 in Erlang/OTP, PuTTY before 0.80, AsyncSSH before 2.14.2, golang.org/x/crypto before 0.17.0, libssh before 0.10.6, libssh2 through 1.11.0, Thorn Tech SFTP Gateway before 3.4.6, Tera Term before 5.1, Paramiko before 3.4.0, jsch before 0.2.15, SFTPGo before 2.5.6, Netgate pfSense Plus through 23.09.1, Netgate pfSense CE through 2.7.2, HPN-SSH through 18.2.0, ProFTPD before 1.3.8b (and before 1.3.9rc2), ORYX CycloneSSH before 2.3.4, NetSarang XShell 7 before Build 0144, CrushFTP before 10.6.0, ConnectBot SSH library before 2.2.22, Apache MINA sshd through 2.11.0, sshj through 0.37.0, TinySSH through 20230101, trilead-ssh2 6401, LANCOM LCOS and LANconfig, FileZilla before 3.66.4, Nova before 11.8, PKIX-SSH before 14.4, SecureCRT before 9.4.3, Transmit5 before 5.10.4, Win32-OpenSSH before 9.5.0.0p1-Beta, WinSCP before 6.2.2, Bitvise SSH Server before 9.32, Bitvise SSH Client before 9.33, KiTTY through 0.76.1.13, the net-ssh gem 7.2.0 for Ruby, the mscdex ssh2 module before 1.15.0 for Node.js, the thrussh library before 0.35.1 for Rust, and the Russh crate before 0.40.2 for Rust.