GoCD is vulnerable to authorization bypass via pipeline structure API

GoCD is a continuous deliver server. From 20.2.0 until 26.1.0, the internal pipeline structure API used for autocompletion while editing pipeline, template, environment, and user-preference configuration returns its users-and-roles mode to regular authenticated users without requiring an administrator role. A lower-privileged user can enumerate configured user names and available role names, which can facilitate attacks against those users. The response does not reveal which roles are assigned to each user, and the endpoint cannot modify data. This issue is fixed in version 26.1.0.