def delete_user_session(user_id, session_key):
    try:
        log.info("Deleted session_key : " + session_key)
        session.query(User_Sessions).filter(User_Sessions.user_id==user_id,
                                            User_Sessions.session_key==session_key).delete()
        session.commit()
    except (exc.OperationalError, exc.InvalidRequestError):
        session.rollback()
        log.exception(e)
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.