From ${URL} : When SSHD tries to authenticate a non-existing user, it will pick up a fake password structure hardcoded in the SSHD source code. On this hard coded password structure the password hash is based on BLOWFISH ($2) algorithm. If real users passwords are hashed using SHA256/SHA512, then sending large passwords (10KB) will result in shorter response time from the server for non-existing users. This allows remote attacker to enumerate existing users on system logging via SSHD. Published in: http://seclists.org/fulldisclosure/2016/Jul/51 @maintainer(s): after the bump, in case we need to stabilize the package, please let us know if it is ready for the stabilization or not.
This issue was resolved and addressed in GLSA 201612-18 at https://security.gentoo.org/glsa/201612-18 by GLSA coordinator Aaron Bauman (b-man).