aria2 is a download utility with resuming and segmented downloading with HTTP/HTTPS/FTP/BitTorrent support.
Tatsuhiro Tsujikawa reported a buffer overflow in DHTRoutingTableDeserializer.cc (CVE-2009-3575) and a format string vulnerability in the AbstractCommand::onAbort() function in src/AbstractCommand.cc (CVE-2009-3617).
A remote, unauthenticated attacker could possibly execute arbitrary code with the privileges of the user running the application or cause a Denial of Service (application crash).
Do not use DHT (CVE-2009-3575) and disable logging (CVE-2009-3617).
All aria2 users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/aria2-1.6.3"