NTP contains the client and daemon implementations for the Network Time Protocol.
Multiple vulnerabilities have been found in the programs included in the NTP package:
A remote attacker might send a specially crafted package to a machine running ntpd, possibly resulting in the remote execution of arbitrary code with the privileges of the user running the daemon, or a Denial of Service. NOTE: Successful exploitation requires the "autokey" feature to be enabled. This feature is only available if NTP was built with the 'ssl' USE flag.
Furthermore, a remote attacker could entice a user into connecting to a malicious server using ntpq, possibly resulting in the remote execution of arbitrary code with the privileges of the user running the application, or a Denial of Service.
You can protect against CVE-2009-1252 by disabling the 'ssl' USE flag and recompiling NTP.
All NTP users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/ntp-4.2.4_p7"