You are running SSH protocol version 1.5. This version allows a remote attacker to decrypt and/or alter traffic via an attack on PKCS#1 version 1.5 knows as a Bleichenbacher attack. OpenSSH up to version 2.3.0, AppGate, and SSH Communications Security ssh-1 up to version 1.2.31 have the vulnerability present, although it may not be exploitable due to configurations.

Patch and New version are available from SSH/OpenSSH.