FreeBSD -- OpenSSH Remote Denial of Service vulnerability

Problem Description:

When processing the SSH_MSG_KEXINIT message, the server could allocate up to a few hundreds of megabytes of memory per each connection, before any authentication take place.

Impact:

A remote attacker may be able to cause a SSH server to allocate an excessive amount of memory. Note that the default MaxStartups setting on FreeBSD will limit the effectiveness of this attack.