The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which allows remote attackers to cause a denial of service (crypt CPU consumption) via a long string.

Affected: Ubuntu:14.04:LTS: openssh, Ubuntu:16.04:LTS: openssh

Eddie Harari discovered that OpenSSH incorrectly handled password hashing when authenticating non-existing users. A remote attacker could perform a timing attack and enumerate valid users. (CVE-2016-6210)

Tomas Kuthan, Andres Rojas, and Javier Nieto discovered that OpenSSH did not limit password lengths. A remote attacker could use this issue to cause OpenSSH to consume resources, leading to a denial of service. (CVE-2016-6515)