Ech0 versions before 4.7.3 expose guest commenter email addresses through public API endpoints due to improper JSON serialization tags on the Comment model. Unauthenticated attackers can harvest all commenter emails by calling the /api/comments and /api/comments/public endpoints without authentication.
Exploitability
AV:NAC:LAT:NPR:NUI:NVulnerable System
VC:LVI:NVA:NSubsequent System
SC:NSI:NSA:N6.9/CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:NInformation Disclosure