FreeRADIUS is an open source RADIUS authentication server implementation.
FreeRADIUS suffers from insufficient input validation in the EAP-MSCHAPv2 state machine.
An attacker could cause the server to bypass authentication checks by manipulating the EAP-MSCHAPv2 client state machine.
There is no known workaround at this time.
All FreeRADIUS users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dialup/freeradius-1.1.1"