vFairs 3.3 is affected by Insecure Permissions. Any user logged in to a vFairs virtual conference or event can modify any other users profile information or profile picture. After receiving any user's unique identification number and their own, an HTTP POST request can be made update their profile description or supply a new profile image. This can lead to potential cross-site scripting attacks on any user, or upload malicious PHP webshells as "profile pictures." The user IDs can be easily determined by other responses from the API for an event or chat room.