Tor is an implementation of second generation Onion Routing, a connection-oriented anonymizing communication service.
A bug in Tor allows attackers to view arbitrary memory contents from an exit server's process space.
A remote attacker could exploit the memory disclosure to gain sensitive information and possibly even private keys.
There is no known workaround at this time.
All Tor users should upgrade to the latest available version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/tor-0.0.9.10"