Transmission is a cross-platform BitTorrent client.
A vulnerability was discovered in how Transmission handles access control through the X-Transmission-Session-Id.
A remote attacker could execute arbitrary RFC commands or consequently conduct a DNS rebinding attack.
There is no known workaround at this time.
All Transmission users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-p2p/transmission-"