# Valve Steam data leak > Live situation record from CLSTR: https://clstr.news/situations/valve-steam-data-leak > Updated: 2026-09-02T16:31:07.000Z. Sources: 60. Developments: 2. A massive data leak, referred to as the ‘Steam Teraleak,’ has surfaced online involving approximately 12 to 13 terabytes of data. The archive contains internal files, development builds, and assets from Valve’s legacy Steam2 content delivery system, spanning the period between 2003 and 2013. Researchers indicate the leak resulted from an unsecured, publicly accessible API endpoint rather than a recent hack. The leaked content includes beta versions and assets for major Valve titles such as Portal 2, Left 4 Dead, Counter-Strike: Global Offensive, and Half-Life. Specific discoveries include unused dialogue, experimental mechanics, and traces of the unreleased Half-Life 2: Episode Three. Additionally, the leak contains information regarding an unreleased project known as ‘F-Stop,’ described as a cancelled Portal prequel. Beyond Valve’s own catalog, the archive includes third-party assets and beta builds for various other games, including Call of Duty, Fallout, and Civilization. A GitHub catalog has been established to compile the leaked titles, and Valve has not yet issued an official statement. ## Timeline ### 2026-09-02: Valve and Steam data leak exposes 12TB of gaming content A massive 12TB data leak from Steam has exposed beta versions and completed games from Valve and other developers, including unreleased projects and historical titles from 2003 to 2013. 3 sources. https://clstr.news/cluster/valve-and-steam-data-leak-exposes-12tb-of-gaming-content ### 2026-08-30: Valve Steam leak exposes 12TB of historical game data A 12TB archive of Valve’s legacy Steam2 data (2003–2013) has leaked via an unsecured API, revealing unreleased prototypes for Portal 2, Half-Life 2: Episode Three, and various third-party game builds. 57 sources. https://clstr.news/cluster/valves-steam2-archive-leak-exposes-12tb-of-gaming-history --- Cite as: Valve Steam data leak. CLSTR, https://clstr.news/situations/valve-steam-data-leak