Activision and Infinity Ward have introduced Server Culling, a system in Call of Duty: Modern Warfare 4 designed to stop wallhacks by withholding the location of hidden opponents from players' devices, according to a video and posts published on the official Call of Duty social media accounts.

Server Culling will cover every multiplayer map available when Modern Warfare 4 launches on October 23, 2026, for PC, Nintendo Switch 2, PlayStation 5, and Xbox Series X/S.

Wallhacks let cheaters see opponents through walls and other cover. The cheat works because game servers normally share information such as a player's position with every game client, even when an enemy is out of sight.

Infinity Ward built occlusion layers into the environments of Modern Warfare 4. With those layers in place, the server limits the information sent to each client to what that player can actually see.

An enemy hiding behind a wall is no longer reported to the device of a player who cannot see that enemy, so cheat software running on that device has nothing to display.

"Cheat software can't reveal information it never receives," the Call of Duty team said. "When a player shouldn't be able to know where an opponent is, the server can now withhold that opponent's location data from their hardware."

Activision states that normal gameplay is not affected. "For legitimate players, the match plays exactly as intended," the publisher said. "For cheat developers, this creates a major new obstacle."

Server Culling is not limited to standard multiplayer. Activision says the system also applies to Combat Outpost, the new mode that takes the place of DMZ, to Warzone, and to future updates. It runs alongside the existing anti-cheat systems on all platforms rather than replacing them.

Server Culling runs on Activision's servers, and the company has not described any setting that players need to turn on. Players planning to start on day one can prepare with a few checks:

1. Confirm the platform: Modern Warfare 4 releases on PC, Nintendo Switch 2, PlayStation 5, and Xbox Series X/S on October 23.
2. Expect Server Culling on every launch multiplayer map, with Warzone and Combat Outpost covered as well.
3. Keep using the in-game reporting tools for suspected cheaters, since Server Culling targets wallhacks and works alongside the other anti-cheat layers.

Modern Warfare 4 also changes double XP tokens so they only count down during matches, and its campaign features a villain played by Mads Mikkelsen.

Activision expects Server Culling to "disturb the cheat marketplace" and says it will not "sit on our hands" after launch. The company has not shared data on how much wallhack use it expects the system to remove, and it has not detailed how it will respond if cheat developers find a way around server-side culling.