The remote host is missing an update to the system as announced in the referenced advisory FreeBSD-SA-06:05.80211.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-06:05.80211.asc

The IEEE 802.11 network subsystem of FreeBSD implements the protocol negotiation used for wireless networking. An integer overflow in the handling of corrupt IEEE 802.11 beacon or probe response frames when scanning for existing wireless networks can result in the frame overflowing a buffer.