FreeBSD Security Advisory (FreeBSD-SA-09:09.pipe.asc)

The remote host is missing an update to the system as announced in the referenced advisory FreeBSD-SA-09:09.pipe.asc
Upgrade your system to the appropriate stable release or security branch dated after the correction date
One of the most commonly used forms of interprocess communication on FreeBSD and other UNIX-like systems is the (anonymous) pipe. In this mechanism, a pair of file descriptors is created, and data written to one descriptor can be read from the other. FreeBSD's pipe implementation contains an optimization known as direct writes. In this optimization, rather than copying data into kernel memory when the write(2) system call is invoked and then copying the data again when the read(2) system call is invoked, the FreeBSD kernel takes advantage of virtual memory mapping to allow the data to be copied directly between processes. An integer overflow in computing the set of pages containing data to be copied can result in virtual-to-physical address lookups not being performed.