Ettercap is a suite of tools for content filtering, sniffing and man in the middle attacks on a LAN.
The curses_msg function of Ettercap's Ncurses-based user interface insecurely implements formatted printing.
A remote attacker could craft a malicious network flow that would result in executing arbitrary code with the rights of the user running the Ettercap tool, which is often root.
There is no known workaround at this time.
All Ettercap users should upgrade to the latest available version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-analyzer/ettercap-0.7.3"