Author: Tina Noma

Valve has reportedly suffered one of the largest video game data leaks ever, with more than 12 terabytes of internal content from its games and Steam distribution platform now circulating online.

The leaked archive reportedly includes material from Valve titles such as Portal 2 and the cancelled Half-Life 2: Episode Three, as well as games from other developers, including Grand Theft Auto V and Dragon Age: Origins.

What is the Steam2 Content Server Dump?

The leak, known as the Steam2 Content Server Dump, emerged on Saturday and quickly spread across social media. Steam2 was Valve’s earlier content distribution system, which the company phased out after introducing SteamPipe in 2013.

Valve used Steam2 to deliver updates through Steam, its digital storefront launched in 2003. The leaked material reportedly came from a Steam2 content server and covers the period from 2003 to 2013.

It remains unclear who was responsible for exposing the data. However, Valve content creator Scolcer claimed that the material was not obtained through hacking, but was instead found on an unprotected website, according to a report translated through Google Translate. Valve-focused content creator Gabe Follower separately corroborated that account.

“No hacking involved, just verified that everything in Steam2 Teraleak was obtained via a publicly accessable [sic] endpoint. It’s Valve’s fault…”

Gabe Follower posted the statement to X, adding:

“That’s why it’s only before 2013, after that they switched to the new storage system.”

Valve game discoveries in the leak

Fans are continuing to examine the archive, which spans a particularly significant period in Valve’s history. During those years, the company released major titles including Half-Life 2, Portal, Team Fortress 2, Left 4 Dead and Dota 2.

Reported discoveries so far include a beta build of Left 4 Dead 2, files apparently connected to the cancelled Half-Life 2: Episode Three, and content removed from Counter-Strike: Global Offensive.

The archive also reportedly contains data related to F-Stop, the cancelled prequel to Portal, along with unreleased but playable versions of Portal 2. Those versions include unused dialogue, plotlines and other features that were not included in the final release.

Mashable has reached out to Valve for comment.

Other games reportedly included

Valve may not be the only developer affected by the Steam2 Content Server Dump. Steam distributes both Valve’s own games and titles published by other companies, and it was already one of the most popular PC game distribution platforms before 2013.

As a result, fans have reportedly identified files or early versions of games including Grand Theft Auto V, Sid Meier’s Civilization V, Call of Duty 4: Modern Warfare, Batman: Arkham Asylum, Dragon Age: Origins, Vampire: The Masquerade – Bloodlines, Mafia II, Spec Ops: The Line and Sonic the Hedgehog 4: Episode II.

In practical terms, games available on Steam in 2013 or earlier may have been present in the leaked data. According to SteamDB, Steam hosted 2122 games by 2013.

More information is likely to emerge as researchers and fans continue to search the archive. However, examining more than 12 terabytes of data could take considerable time. In 2024, approximately 1 terabyte of data was leaked from Nintendo’s servers in an incident dubbed the “Teraleak,” followed by a second release a year later. Despite being much smaller than the Valve leak, that archive continued to reveal new information through last month.