Users of Linksys EtherFast Cable/DSL Routers should upgrade to the latest firmware to avoid a vulnerability discovered by security firm iDEFENSE. It's not a huge problem, the most likely thing that could happen would be that an intruder could cause you to lose internet connectivity. Hitting reset on the router would restore your access. (More information from PCWorld.com)
Firmware updates are available at the Linksys website.