OpenAEV is an open source platform allowing organizations to plan, schedule and conduct cyber adversary simulation campaign and tests. Prior to version 2.260622.0, on a default installation, the "/api/player/**" lessons endpoints can be called without authentication, and they trust a client-supplied "userId" query parameter without verifying that the caller is that user or a member of the exercise. An unauthenticated client that knows an exercise UUID can read lessons-learned questions and answers (including each answer's author identity) and create or overwrite answers attributed to an arbitrary user. Version 2.260622.0 contains a patch.