FreeBSD Security Advisory (FreeBSD-SA-04:01.mksnap_ffs.asc)

The remote host is missing an update to the system as announced in the referenced advisory FreeBSD-SA-04:01.mksnap_ffs.asc

Mounted filesystems can have a variety of flags set on them. Some flags affect performance and reliability, while others enable or disable particular security-related features such as the ability to execute a binary stored on the filesystem or the use of access control lists to complement normal Unix file permissions. The mksnap_ffs(8) command creates a `snapshot' of a filesystem. A `snapshot' is a static representation of the state of the filesystem at a particular point in time. Snapshots have a variety of uses, but their primary purpose is to make it possible to run fsck(8) and dump(8) on live filesystems. The kernel interface for creating a snapshot of a filesystem is the same as that for changing the flags on that filesystem. Due to an oversight, the mksnap_ffs(8) command called that interface with only the snapshot flag set, causing all other flags to be reset to the default value.

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-04:01.mksnap_ffs.asc