FreeBSD has acknowledged a vulnerability in telnetd, which can be exploited by malicious people to compromise a vulnerable system.

The vulnerability is caused due to a boundary error within the "encrypt_keyid()" function (crypto/heimdal/appl/telnet/libtelnet/encrypt.c and contrib/telnet/libtelnet/encrypt.c), which can be exploited to cause a buffer overflow by sending specially crafted commands to the server.

NOTE: This vulnerability is currently being actively exploited.

Solution
Update FreeBSD or apply patch.

Provided and/or discovered by
Reported by the vendor.

Original Advisory
FreeBSD-SA-11:08.telnetd:
http://security.freebsd.org/advisories/FreeBSD-SA-11:08.telnetd.asc

Deep Links
Links available to Secunia VIM customers