A major security hole has been found in Ruby on Rails. Upgrading to version 1.1.5 is extremely urgent, and all previous versions except those “on a very recent edge” are affected. Details on the exact nature of the flaw will be coming soon, but the rails team has decided to wait a short time before disclosure so that people can have a chance to upgrade their servers before would-be-assailants are armed.
If your server runs Rails, upgrade the software right now. They don’t say “Major” just for the fun of it.