Valve's Steam Server Bugs Could've Let Hackers Hijack Online Games

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.
“An attacker could remotely crash an opponent’s game client to force a win or even perform a ‘nuclear rage quit’ and crash the Valve game server to end the game completely,” Check Point
Source: thehackernews.com