Ech0 before 4.4.3 protects the PUT /user endpoint with the profile:read scope, a read-only scope, but allows write operations including password changes. An attacker with an admin's profile:read access token can change the admin's password and login to obtain an unrestricted session token that bypasses all scope enforcement.
Exploitability
AV:NAC:LAT:NPR:HUI:NVulnerable System
VC:HVI:HVA:NSubsequent System
SC:NSI:NSA:N8.5/CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NAccess Control