l2tpd is a GPL implentation of the Layer 2 Tunneling Protocol.
Thomas Walpuski discovered a buffer overflow that may be exploitable by sending a specially crafted packet. In order to exploit the vulnerable code, an attacker would need to fake the establishment of an L2TP tunnel.
A remote attacker may be able to execute arbitrary code with the privileges of the user running l2tpd.
There is no known workaround for this vulnerability.
All users are recommended to upgrade to the latest stable version:
# emerge sync
# emerge -pv ">=net-l2tpd-0.69-r2"
# emerge ">=net-l2tpd-0.69-r2"