Samba is a freely available SMB/CIFS implementation which allows seamless interoperability of file and print services to other SMB/CIFS clients.
Samba contains a bug when unmarshalling specific MS-RPC requests from clients.
A remote attacker may be able to execute arbitrary code with the permissions of the user running Samba, which could be the root user.
There is no known workaround at this time.
All samba users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-fs/samba-3.0.9-r1"