Supply Chain Alert: MangaGamer Higurashi USB Installers Compromised with Possible Floxif Malware
MangaGamer has issued a warning about a potential supply-chain attack: in the latest print run of the physical edition of Higurashi When They Cry Hou+, the Windows installers on the included USB drive appear to have been compromised. Customers who purchased the USB hardcopy after July 9, 2025—or, according to a later clarification, possibly as early as July 3—are advised not to use the flash drive to install the game while the investigation and legal consultations are ongoing.
The company stresses that the digital editions of Higurashi When They Cry Hou+ available on MangaGamer.com, Steam, and GOG are not affected. MangaGamer estimates that approximately 64–67 units from the potentially compromised batch were sold: 16 through conventions, 10 wholesale to a third-party retailer, and roughly 38–41 directly via its own store.
MangaGamer reports that it is already processing refunds for traceable card payments. Orders that included unreleased preorder items will receive corrected copies of Higurashi Hou+ when the remainder of the order ships. Customers who purchased the USB version at a convention or from a third-party seller and suspect they received an affected copy are encouraged to contact support at support@mangagamer[.]com with the subject line “Higurashi USB.”
According to the company, the compromised installers should be detected by Windows Defender and can be distinguished from the originals by file size. As an example, the installer for the first chapter measures 267.69 MB in its original form, compared to 268.42 MB for the compromised version. On December 12, 2025, MangaGamer also clarified that multiple installers are present on the USB drive.
If installation from a suspicious USB has already occurred, MangaGamer believes the malicious code may be related to the Floxif virus. Based on current findings, only the Windows installers appear to be affected. The company recommends running a full system scan using Windows Defender or a reputable third-party antivirus if there is any concern about compromise.
MangaGamer emphasizes that the indicators point to an issue confined to this specific print run and this particular release. Nevertheless, “out of an abundance of caution,” sales of all USB physical editions produced alongside or after the affected batch of Higurashi Hou+ have been temporarily suspended pending further inspection.
The company also notes that while its titles have triggered false antivirus positives in the past, this is the first time it has acknowledged the possibility of a genuine attack on its products. Preorders for physical editions remain open, though release timelines may shift as a result of the incident, and MangaGamer has pledged to share updates as more information becomes available.
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