SurveyKing before 1.13.0 contains a missing authorization vulnerability that allows unauthenticated attackers to download any stored file by id through GET /api/public/preview/{attachmentId}. Attackers who know or derive time-ordered snowflake file ids can bypass shared, owner, and project checks in FileServiceImpl.loadFile to read private survey attachments and respondent uploads.
SurveyKing v0.2.0 was discovered to retain users' session cookies after logout, allowing attackers to login to the system and access data using the browser cache when the user exits the application.