netkit-telnetd provides standard Linux telnet client and server.
A buffer overflow has been identified in the slc_add_reply() function of netkit-telnetd client, where a large number of SLC commands can overflow a fixed size buffer.
Successful explotation would require a vulnerable user to connect to an attacker-controlled host using telnet, potentially executing arbitrary code with the permissions of the telnet user.
There is no known workaround at this time.
All netkit-telnetd users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/netkit-telnetd-0.17-r6"