Tor is an implementation of second generation Onion Routing, a connection-oriented anonymizing communication service.
Tor contains a heap-based buffer overflow in the processing of user or attacker supplied data. No additional information is available.
Successful exploitation of this vulnerability may allow an unauthenticated remote attacker to execute arbitrary code with the permissions of the Tor user, or to cause a Denial of Service.
There is no known workaround at this time.
All Tor users should upgrade to the latest stable version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/tor-0.2.1.28"