Valve has issued a server-side fix to stop cheaters from taking advantage of Left 4 Dead exploits on the Xbox 360. Reported cheats allowed players to spawn infinite items and enemies in online games.
A follow-up statement from Valve says that the fix has already been deployed to address cheats on dedicated Xbox Live servers, which accounts for the majority of co-op and versus mode play.
It expects to deploy a title update "in the coming days" for Xbox 360 owners playing on user-hosted servers or via system link. Thanks, Valve!