The remote host is missing an update to the system as announced in the referenced advisory FreeBSD-SA-10:05.opie.asc

Upgrade your system to the appropriate stable release or security branch dated after the correction date https://secure1.securityspace.com/smysecure/catid.html?in=FreeBSD-SA-10:05.opie.asc

OPIE is a one-time password system designed to help to secure a system against replay attacks. It does so using a secure hash function and a challenge/response system. OPIE is enabled by default on FreeBSD. A programming error in the OPIE library could allow an off-by-one buffer overflow to write a single zero byte beyond the end of an on-stack buffer.