OpenSSH-portable (OpenSSH) 3.6.1p1 and earlier with PAM support enabled immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.
OpenSSH 3.0.1 and earlier with UseLogin enabled does not properly cleanse critical environment variables such as LD_PRELOAD, which allows local users to gain root privileges.
OpenSSH before 2.9.9, when running sftp using sftp-server and using restricted keypairs, allows remote authenticated users to bypass authorized_keys2 command= restrictions using sftp commands.
OpenSSH before 2.9.9, while using keypairs and multiple keys of different types in the ~/.ssh/authorized_keys2 file, may not properly handle the "from" option associated with a key, which could allow remote attackers to login from unauthorized IP addresses.
The "echo simulation" traffic analysis countermeasure in OpenSSH before 2.9.9p2 sends an additional echo packet after the password and carriage return is entered, which could allow remote attackers to determine that the countermeasure is being used.