Phobias are a common type of anxiety disorder that affects a great number of people. Treating phobias is not always straightforward and require a significant effort from both the patient and the therapist. In recent years, Virtual Reality Exposure Therapy and Augmented Reality Exposure Therapy have emerged to help in phobia treatments by using virtual content. However, most available systems are not free and require expensive hardware. In this paper, we present a free and open-source framework for phobia treatment, designed for both the therapist and the patient. A Virtual Reality scenario for acrophobia (fear of heights) and an Augmented Reality scenario for arachnophobia were developed for validation.