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Reviewed and published by trentmaziarz, March 22, 2026. Discovered and drafted by our automated research pipeline.
VAC Live is Valve's upgraded anti-cheat system for Counter-Strike 2, running machine learning analysis during live matches — not after the fact — so it can detect cheating in real time and cancel an affected match immediately. It replaced the earlier VACnet system when CS2 launched in 2023.
Details
Unlike VACnet, which analyzed completed matches and sent suspicious cases to human reviewers, VAC Live identifies and responds to cheating while the match is still in progress, issuing instant bans and voiding the game. Valve's official developer wiki describes it as "a server-sided machine learning approach which tries to detect any irregular gameplay." A reported August 2024 expansion extended detection to hardware-level cheats, including specialized devices used to bypass software-based detection. A September 2025 update was widely reported to have disrupted the CS2 cheating ecosystem significantly. Over 4.5 million accounts have been banned for cheating in Counter-Strike 2 to date.
Products affected
Counter-Strike 2 (CS2)
Sources & Evidence
Company Disclosure
Other practices by Valve Corporation
OtherValve holds multiple patents describing machine learning applications for its hardware products and multiplayer networking. These cover predicting player input to reduce lag in online games, tracking eye gaze direction in VR headsets, and determining the physical position of a VR headset using sensor data. The patents confirm Valve's machine learning R&D extends well beyond anti-cheat.ProductivityA Valve engineer publicly described using ChatGPT like an advanced search engine to find a specific type of matching algorithm he needed for the game Deadlock. He found the Hungarian algorithm this way and it was then built into Deadlock's hero selection matchmaking system. The engineer shared this on social media in October 2024.ModerationSteam operates a text filtering system in Steam Chat and in games like Counter-Strike 2 and Dota 2, automatically blocking or replacing profanity and slurs. Players can adjust how much filtering is applied to their own experience. The system shipped as Steam Labs Experiment 011 before being integrated into the main platform.
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