Steam2 leak reveals pre-2013 builds from hundreds of PC games
A massive archive from Steam’s old content delivery system has appeared online, reportedly containing around 12TB of game files dating from 2003 to 2013. The leak was first discussed primarily for its Valve content, but researchers now say the archive contains thousands of Steam depots covering hundreds of games from multiple publishers.
Data reportedly came from a public Steam2 endpoint
According to Gabe Follower, the files were not obtained through a conventional security breach. He says researchers verified that the content was available through an incorrectly exposed endpoint connected to Valve’s old Steam2 infrastructure.
“No hacking involved, just verified that everything in Steam2 Teraleak was obtained via a publicly accessable endpoint. It’s Valve’s fault…”
Someone leaked 12 TB of Valve's internal builds and game assets from 2003 to 2013. This includes early versions of Portal 2, Left 4 Dead, CS:GO, F-Stop and potentially EP3. The community is still researching everything, so the next few days might be insane… There's a Weaponizer… pic.twitter.com/Sg7OqJjL2X
— Gabe Follower (@gabefollower) August 29, 2026
Gabe Follower says the archive contains Valve material spanning 2003 to 2013, including early versions of Portal 2, Left 4 Dead and Counter-Strike: Global Offensive. F-Stop assets have also been discovered. One early CS:GO build reportedly dates from a stage when the game was still based more directly on Counter-Strike: Source.
The files may also contain material associated with Half-Life 2: Episode Three. Researchers have already identified a model for the Weaponizer, a weapon previously associated with the cancelled game. However, there is currently no evidence that a complete or playable Episode Three build is included in the archive.
The archive extends beyond Valve games
The Steam2 dump apparently includes third-party games as well. Several beta builds of Sonic the Hedgehog titles have already been identified, including Sonic 4 Episode II. Community researchers have also reported files connected to Fallout: New Vegas and other games released through Steam during this period.
Steam2 was Valve’s older content delivery system, which stored game content using formats such as GCF before Steam transitioned to SteamPipe. Valve moved games to the newer system during the early 2010s, with many migrations taking place in 2013.
Community researchers are still cataloging the archive, so the confirmed list of development builds and unreleased material is likely incomplete. Valve has not yet issued any public statement; perhaps they are evaluating what was leaked as well.
Source: Contents of the leak (Github)