Steam API glitch briefly exposed achievements for dozens of unreleased, unannounced games

An apparent Steam API visibility error briefly exposed achievement data for dozens of unreleased and unannounced games early Wednesday, creating immediate spoiler concerns and surfacing titles that had not been formally detailed in public. Valve had not publicly commented on the issue as of about 17:56 UTC on Sept. 9.

The exposed data appeared through Steam-related tools and APIs and was quickly indexed by third-party sites including Exophase, a game achievement tracker, and SteamDB, which monitors Steam app metadata. According to Gematsu and other contemporaneous reports, affected entries included high-profile announced games such as Persona 6, Kingdom Hearts IV, Fable, Silent Hill: Townfall, Gears of War: E-Day and Ace Combat 8, along with a range of apparently unannounced projects.

The strongest public examples showed that the leak went well beyond bare app names. Exophase displayed a Persona 6 achievements page listing 48 achievements with descriptive text, indicating the exposed metadata could reveal story details, locations, endings or gameplay systems. SteamDB, meanwhile, showed a KINGDOM HEARTS IV app entry, AppID 3216600, with a “Last Record Update” timestamp of Sept. 9, 2026, at 03:26:42 UTC, suggesting Steam metadata for that title became visible during the same window.

The working explanation, based on public reporting and comments from Exophase’s operator, is that the exposure stemmed from a Valve-side permissions or API problem rather than a breach of the tracker itself. Mike Bendel, who runs Exophase, wrote in a ResetEra post quoted by Gematsu: “Seems like a possible screw up on Valve’s end, a bunch of games with achievements that should be private are accessible through the API right now and that’s why they got scanned into the site.” Valve has not publicly confirmed that explanation or offered an on-the-record statement about the cause.

That distinction matters because Steam achievements are developer-configured metadata distributed through Steamworks, Valve’s developer tools and services for publishing on Steam. Steam’s Web API documentation shows achievement schemas can be returned through the ISteamUserStats interface, which helps explain how sites such as Exophase can automatically index them once they become accessible. When those schemas are public, they often contain plain-language names and descriptions that can spoil major plot points or disclose features publishers have not announced.

The scale of the exposure remains unclear. Early reports described roughly 50 or more affected titles, while other roundups cited more than 100 and in some cases 145-plus. There is no single authoritative public count as of Wednesday, and those figures should be treated cautiously.

Just as important, appearing in leaked achievement data or app metadata is not definitive proof that every listed project will be commercially released. Some surfaced entries could reflect placeholders, internal tests or projects that never ship. What is clear is that a brief apparent Steam visibility failure exposed sensitive game metadata widely enough for third-party trackers to capture it, turning backend publishing data into public spoilers and premature reveals before Valve or publishers had explained what happened.