Valve suffers massive 12TB leak, revealing a decade of Steam game files

Valve suffers massive 12TB leak, revealing a decade of Steam game files

Valve has reportedly suffered a massive leak, with over 12 terabytes of the game developer's internal data now available online.

A massive 12TB of game-related files, the largest ever leaked from Steam, have been discovered.

On August 29, 2026, local time, 12TB of game-related files were leaked onto the internet from Steam , the PC game platform operated by Valve. It has been revealed that not only internal builds of games developed by Valve, but also beta builds of games developed by various game companies, both large and small, were leaked. Steam Just Suffered the Biggest Leak in Video Game History https://www.polygon.com/steam-leak-valve-portal-2-beta-half-life-3…

12 TB of Valve's Old Game Builds Reportedly Appeared Online

Early builds for Portal 2, CS: GO, Left 4 Dead, and more are in the archive.

The Steam 'teraleak' extends far beyond Valve games, including prototypes of third-party titles like Mafia 2 and Grand Theft Auto 3: 'This may be one of if not the biggest leaks to occur'

Hundreds of Steam file groups were included in the leak relating to game builds, trailers, soundtracks and more.