Heimdal is a free implementation of Kerberos 5.
A boundary error in the "encrypt_keyid()" function in appl/telnet/libtelnet/encrypt.c of the telnet daemon and client could cause a buffer overflow.
An unauthenticated remote attacker may be able to execute arbitrary code with the privileges of the user running the telnet daemon or client, or cause Denial of Service.
There is no known workaround at this time.
All Heimdal users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-crypt/heimdal-1.5.1-r1"