Easy!Appointments Vulnerable to Appointments Takeover via Excessive Data Exposure

Easy!Appointments is a self hosted appointment scheduler. In version 1.5.2, an Excessive Data Exposure vulnerability in the customers search endpoint allows an authenticated user to obtain appointment hashes belonging to other users.
Using these hashes, an attacker can modify or delete appointments of other providers, resulting in an Appointments Takeover. Version 1.6.0 fixes the issue.