wger vulnerabilities

In wger prior to version 2.6, there is a vulnerability that allows a user with gym.manage_gym permissions to reset the password of any user with no gym assignment. By exploiting an object comparison error, an attacker can take over the victim's account, and the victim's original password is invalidated.

In wger prior to version 2.6, a gym trainer can escalate their session to any higher-privileged account (gym manager, general manager) by chaining two calls to the trainer-login endpoint. After a legitimate switch to a low-privileged user, the session flag `trainer.identity` is set and bypasses permission checks on subsequent trainer-login calls.

In wger versions prior to 2.6, an authenticated user can read another user's private workout notes, exercise history, and training statistics by calling the /logs/ and /stats/ actions on a routine they do not own. The vulnerability is due to incorrect permission checks in RoutineViewSet, which grants read access to any authenticated user when the routine has is_template=True.