Since release, Call of Duty: Modern Warfare has had numerous issues that have affected the multiplayer. Primarily the audio issues, player hitbox, weapon balancing and spawn system. Now we have invincible players who can not be killed or kill other players and a wallhack glitch has recently appeared.
Reddit user, Al24lo, shared a video of their gameplay over on the Modern Warfare subreddit. While playing the map St Petrograd, you can see them running around in a normal multiplayer game with the walls glitching in and out. This player is a PC player as you can see the hotkeys showing on the screen during the gameplay.
Now, this doesn’t appear to be a one time thing. The comments in the post show that others in the community have experienced similar bugs to them within the past week or so. One person saying it happened on every map he loaded and had to reboot the game to stop it.
Seeing how this has been an on-going bug, it may not be an easy fix for Infinity Ward.