[Soyweiser]

Originally Posted by vfb

In-game messages like "I'm setting taxes to 0% so you go bankrupt" can cause the turn to crash when they are viewed.

The game formats messages that are displayed on the screen using one of the printf calls. It should pass ( ..., "%s", message ) for user-entered messages. But instead it passes ( ..., message ). So if 'message' contains printf formatting, it will expect additional arguments. And if the printf code is '%s' (spaces between the '%' and 's' don't matter), it will treat whatever happens to be on the stack as an address to read a string from. If this address is invalid, that can cause a crash.

This is a serious problem. This can cause much more than a simple crash. If someone makes a malicious message, it could take over your computer.

http://en.wikipedia.org/wiki/Format_string_attack