TP-Link TL-WDR4300 can run OpenWrt [1], a highly modular Linux distribution meant primarily for routers. If you have one of those routers and you're at all familiar with Linux should really consider upgrading to OpenWrt. Once you've got the web UI set up administering it becomes very similar to configuring "normal" routers.
Unfortunately, stock firmware that comes with a lot routers has just been no good even if it lacked gaping security holes like this. Fortunately, there are community-developed FOSS alternatives that offer a better user experience; I imagine that having more eyes on the source also helps their security. I use TomatoUSB [2] on my main router (Asus RT-N66U) and OpenWrt on the "experimental" one (TP-Link TL-MR3020) and can highly recommend both distributions.
Unfortunately, stock firmware that comes with a lot routers has just been no good even if it lacked gaping security holes like this. Fortunately, there are community-developed FOSS alternatives that offer a better user experience; I imagine that having more eyes on the source also helps their security. I use TomatoUSB [2] on my main router (Asus RT-N66U) and OpenWrt on the "experimental" one (TP-Link TL-MR3020) and can highly recommend both distributions.
[1] http://wiki.openwrt.org/toh/tp-link/tl-wdr4300
[2] http://tomatousb.org/