Summary
The remote host is missing an update to the system as announced in the referenced advisory.
Solution
Update your system with the appropriate patches or software upgrades.
http://dist.schmorp.de/rxvt-unicode/Changes
http://www.vuxml.org/freebsd/c2fdb3bc-7d72-11da-b96e-000fb586ba73.html
Insight
The following package is affected: rxvt-unicode
