Steam API Glitch Reveals Persona 6, Kingdom Hearts 4 Achievements and Other
A significant security lapse within Valve’s Steam platform on September 9, 2026, inadvertently exposed hundreds of achievement lists for upcoming and unannounced video games. This major Steam leak offered an unexpected glimpse into highly anticipated titles such as Atlus’s Persona 6, Square Enix’s Kingdom Hearts 4, and even completely new projects that haven’t yet seen formal announcements.
The incident originated from what appears to be a flaw in Valve’s Application Programming Interface (API) during its weekly maintenance, allowing third-party achievement tracking sites like Exophase and SteamDB to scrape and publicly display data that should have remained private.
Glitch reveals persona: Valve’s API leak
This accidental disclosure has ignited a firestorm across the gaming community, with developers facing the premature revelation of plot points and game mechanics, while eager players grapple with potential spoilers. The leak also highlighted the extensive Square Enix titles in the pipeline.
The sudden influx of previously hidden achievement data is attributed to a “screw-up” on Valve’s end, according to Mike Bendel, owner of Exophase. He noted in a ResetEra post that games without official names typically don’t appear with accessible achievements. But on September 9, the system suddenly made a wealth of private information available through the API.
Automated data collection websites were quick to record these newly public achievement lists. This technical glitch transformed what should have been confidential development details into readily available information, revealing not just confirmed titles but also hinting at games that might be in early development or even have been cancelled.
The exposed achievements, while often containing placeholder text, are rich with potential spoilers. Gamers have already begun dissecting these lists, uncovering details ranging from narrative beats to gameplay elements and even new in-game worlds. This has prompted many to suggest muting keywords online to avoid unintended revelations.
Impact on Major Titles like Persona 6
For fans of the Persona series, the leak confirmed achievement details for the highly anticipated Persona 6. Atlus and Sega had formally announced the game with a teaser trailer during the Xbox Games Showcase on June 7, 2026, building considerable excitement.
Persona 6 is set to launch on PlayStation 5, Windows, and Xbox Series X/S, marking a significant shift from the series’ traditional PlayStation exclusivity by being available day one on Xbox Game Pass.
While previous leaks and a translator’s comments in June 2026 had suggested a September 2027 release date, this new achievement data offers fresh insights into the game’s scope and content. This incident offers a glimpse into Steam’s platform growth.
Kingdom Hearts 4 Details Emerge Unexpectedly
The leak also unveiled new information for Kingdom Hearts 4, the next installment in Square Enix’s popular Disney-themed action RPG franchise. The game was officially announced back in April 2022, with a new trailer offering cinematics and combat details shown during the June 2026 Nintendo Direct.
Square Enix confirmed at D23 in August 2026 that Kingdom Hearts 4 is slated for a “late 2027” release across Nintendo Switch 2, PlayStation 5, Xbox Series X|S, and PC via Steam and Epic Games Store, a simultaneous day-one launch. The leaked achievements have provided specifics on Disney-themed worlds and story elements, potentially spoiling some of the magical journey for players.
Other Unannounced Games Uncovered by the Leak
Beyond the highly anticipated sequels, the Steam leak shone a spotlight on a host of other titles previously unconfirmed or kept under wraps. This included achievements for games like Fable, Control Resonant, and Gears of War: E-Day.
The data also hinted at potential future projects such as Ace Combat 8, Metro 2039, Star Wars: Galactic Racer, Silent Hill: Townfall, Horizon Hunters Gathering, Judas, Minecraft Dungeons 2, and Dragon Ball Xenoverse 3.
Furthermore, the leak even suggested entirely unannounced titles like a “Dune game,” a “Twin Peaks game,” and a “Shrek 2 Remaster,” though these may be placeholder entries or projects in very early stages.
The presence of placeholder text within many of these achievement lists indicates they are likely still under active development, or perhaps have been abandoned. For developers, this type of premature exposure can be disruptive, impacting their marketing strategies and the carefully planned reveals meant to build anticipation.
Broader Implications for Game Development and Publishing
This latest Steam leak underscores the constant tension between platform security and the industry’s need for secrecy around unreleased projects. Game developers frequently voice “frustration, anger, helplessness” when leaks occur, feeling that it “robs hard working teams of revealing on their terms,” as expressed by Cory Barlog, director of God of War.
The implications extend beyond mere disappointment. Leaks can have significant legal ramifications, particularly if they violate non-disclosure agreements (NDAs) or end-user license agreements (EULAs). Companies like Epic Games have pursued lawsuits against leakers for damages, demonstrating the financial and reputational stakes involved.
Valve’s History of Security Incidents
This isn’t Valve’s first encounter with significant data exposure. Just last month, in July 2026, the company confirmed that European customer data was compromised following a breach at CEVA Logistics, Valve’s regional shipping partner for Steam hardware. That incident affected names, addresses, phone numbers, and email addresses.
Going back further, a “SMS incident” in 2025 prompted Valve to recommend alternative two-factor authentication methods, highlighting ongoing challenges in maintaining robust cybersecurity. These repeated incidents raise questions about Valve’s internal security protocols and their ability to safeguard sensitive information, including that of its development partners.
Navigating Spoilers and the Future of Game Leaks
For players, the immediate challenge is navigating the deluge of new information without encountering unwanted spoilers. The gaming community is adept at dissecting such leaks, so anyone hoping to experience these games fresh will need to exercise caution online, perhaps by temporarily muting specific game titles or related keywords on social media platforms.
The incident highlights the difficult position developers find themselves in, trying to control the narrative around their games. While leaks can sometimes generate unexpected buzz, they more often undermine carefully crafted marketing campaigns and spoil narrative surprises. It also underscores the inherent vulnerabilities in digital distribution platforms, even those as established as Steam.
Moving forward, both Valve and other platform holders will likely face increased scrutiny over their data security practices. The frequency and scale of these future game launches revelations suggest a need for more stringent internal controls and improved API security to prevent future “screw-ups” that compromise sensitive information.
The gaming industry, always pushing boundaries with new experiences, also needs to secure the pipeline bringing those experiences to players.
Ultimately, while a leak can provide an early, albeit unintended, look at future titles, it comes at a cost. Developers lose control over their reveals, and players risk having their first experiences tainted by premature disclosures. This balance of excitement versus secrecy will continue to define the challenges faced by the digital gaming ecosystem.