Steam has apparently been the site of one of the biggest gaming leaks in recent months. Achievement lists for dozens of unreleased games suddenly became publicly accessible through Valve’s API, and the tracking site Exophase automatically captured them. Affected titles include big names like *Persona 6*, *Kingdom Hearts IV*, *Fable*, *Horizon Hunters Gathering*, *Silent Hill: Townfall*, and *Control Resonant*. Even more explosive: the dump includes several titles that have not been announced at all. Some lists contain major story spoilers, so we are not reproducing them. The sheer scale of the incident is notable.
At this point, the leak does not appear to be the result of a traditional hacking attack; instead, private data may have been temporarily accessible through the Steam API.
Exophase automatically discovered the data.
Exophase automatically scans for achievements and builds databases for individual games. Site operator Mike Bendel said that many titles with achievement lists that should have remained private suddenly appeared.
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He believes the exposure resulted from a possible error on Valve’s end, as the private achievement data was briefly accessible through the API and was automatically scanned by Exophase. Valve has not yet publicly explained the technical background of the incident.
Persona 6 Is Particularly Hard Hit
One of the most prominent titles is Persona 6. Exophase currently lists 48 Steam achievements for the upcoming Atlus RPG. This is particularly sensitive because Persona 6 has had relatively few official story details revealed so far. The achievement descriptions mention various events, mechanics, and apparently key plot points.
Anyone who wants to experience Persona 6 with as little prior knowledge as possible should therefore be especially cautious when it comes to such lists and discussions on social media at this time.
We are deliberately refraining from repeating the relevant story details here. However, the mere existence of such an extensive list of achievements suggests that the game’s basic structure is likely already well advanced internally. This is not confirmation of an imminent release. Achievement data can be created long before a game’s release.
Kingdom Hearts IV Apparently Reveals New Worlds
Kingdom Hearts IV faces a similar issue. Exophase currently lists 50 achievements for the game, and some appear to hint at worlds that Square Enix has not yet officially revealed. Gematsu therefore explicitly warns of possible spoilers.
As with Persona 6, the list is drawn from Steam data but Square Enix has not verified its accuracy. Fans should avoid spoilers and remember that names, tasks, and even entire sections may change before launch.
Several unannounced games also appear
The leak also lists several unannounced titles, including Attack on Titan 3, Dragon Ball Xenoverse 3, Minecraft Dungeons II, Metro 2039, and Planet Zoo 2.
Rayman Legends: Retold, Thief: The Dark Project Remastered, and Terranigma. The list also mentions an unannounced Telltale The Walking Dead project, a new Tetris game, and other unknown titles.
Steam entries are sometimes created for projects that are later modified, renamed, or canceled. Still, it would be unusual for so many detailed achievement lists to appear out of thin air.
Numerous already-known PS5 games are also included
The list is also notable for PlayStation players. In addition to *Persona 6* and *Kingdom Hearts IV*, it includes *Horizon Hunters Gathering*, *Silent Hill: Townfall*, *Judas*, *Kena: Scars of Kosmora*, *Control Resonant*, *Ace Combat 8*, and *Tomb Raider: Legacy of Atlantis*, among others.
This means the leak affects a wide range of major games also coming to PlayStation. For titles still far off, achievement lists may contain details publishers intended to reveal much later.
Is the Steam leak real?
Several factors suggest that internal Steam data has indeed been made public. Exophase did not manually pull the achievement lists from an anonymous forum; according to the site’s operator, the data came directly from the Steam API. For *Persona 6* and *Kingdom Hearts IV*, the corresponding achievement pages are currently viewable directly on Exophase.
Valve, Atlus, Square Enix, and the other affected publishers have not issued official confirmations. Two points remain distinct: Exophase likely accessed the data through Steam, but the information has not been verified as matching the current state of each game’s development.
For players, the main concern right now is the risk of spoilers
For publishers, the leak is unpleasant. For players, the immediate issue is different. Some achievement descriptions apparently reveal significantly more than typical trophy lists do so close to launch. Persona 6 is even said to contain key story details, and Kingdom Hearts IV may reveal previously unannounced worlds.
Anyone eager to start either title fresh should avoid Reddit, X, YouTube thumbnails, and related forums in the coming days. The remarkable part of the story remains the scale: a possible bug in Valve’s API briefly exposed internal data for dozens of upcoming games.
Some of those titles were unknown to the public until yesterday. Source: https://www.gematsu.com/2026/09/persona-6-kingdom-hearts-iv-and-other-steam-achievements-surface-in-large-scale-leak Let us know your thoughts in the comments.
