Critical flaws in a core networking library powering Valve’s online gaming functionality could have allowed malicious actors to remotely crash games and even take control over affected third-party game servers. The four flaws were uncovered in Valve’s Game Networking Sockets library, an open-sourced networking library. Check Point Research’s Eyal Itkin said that gamers playing Valve’s games through Steam are already protected by the fix. The fix was released to Valve on September 2, 2020, with the fixes shipped to Valve’s game clients and servers on September 17.
Source: https://thehackernews.com/2020/12/valves-steam-server-bugs-couldve-let.html