FreeBSD contains a flaw that may allow a malicious user to gain the access privileges of the "man" user. The issue is triggered when a special sequence of commands are executed. It is possible that the flaw may lead to root access via a trojan horse resulting in a loss of integrity.
Upgrade to version FreeBSD 2.1-STABLE, or 2.2-CURRENT dated 1996-05-21 or later, as it has been reported to fix this vulnerability. It is also possible to correct the flaw by implementing the following workaround: disable the setuid bit on the /usr/bin/man file.
#chmod u-s /usr/bin/man